Marine Fish Diseases and Parasites

When seeking online help in diagnosing a fish disease or parasite, I have found that a great deal of time is spent trying to properly describe the problem to where others can be of help. Since a good many fish diseases do not give you, or the fish, a great deal of time to waste discussing for days what possible issues are effecting the fish, I have done my best to put together a pictorial guide in the hopes that it will allow you to better identify exactly what is ailing your fish.
If you are able to identify a disease or parasite on your fish, and have a good photograph, please submit it for use within this webpage in order to allow others a better chance at correctly diagnosing the same problems you have encountered. To do so, please use my contact page. Thank you.

Also available for corals

CORAL DISEASES & PARASITES

Generally,the oceans can be considered a somewhat stable environment that experiences limited fluctuations within its water parameters, such as salinity, pH and temperature. It is due to the upper and lower limits encountered on a typical tropical reef that most of its inhabitants are unable to tolerate any extremes that may occur above or below their normal swings.
As such, we must ensure that our aquariums do not experience rapid or extreme differences to what can be found in a natural tropical environment. When we transfer creatures from their native habitats to aquariums, we must consider that everything must be within their naturally occurring tolerances, there is little room for error. The following concerns should be taken into account when maintaining your aquarium and with the stocking of its inhabitants.

Please take into consideration -

1 - Water quality. This area of aquarium keeping is of great importance for obvious reasons and covers a wide range of parameters which you must become familiar with and able to provide to the occupants of your aquarium. Providing the proper environment is of course critical to the health of any organism placed within our aquariums. When your fish encounter a problem, the quality of their water should be the first item on your check list as to possible causes of poor health.

2 - Compatibility. Many reef fish such as the damsels and angelfish are territorial, vigorously defending either an individual or a pair's territory against all other fish, especially con specifics. This behavior, essential on a highly populated reef, may cause problems in the confines of small aquariums, stressing not only the other tank inhabitants, but also the territorial individuals themselves who will be unable to drive the "interlopers" from their territory. An alternative lifestyle is that of shoaling where the fish congregate in large schools thereby reducing the chances of an individual being predated, but also helping to maximize the use of certain food resources and to increase the opportunity for male-female interactions for spawning. A classic example of these would be the Anthia and Chromis species. However due to the low stocking densities of marine aquaria, the relatively high price of individual fish, and the tendency for many aquarists to want "one of each" these fish are rarely kept in the correct social numbers or groupings.

Not only must we consider the compatibility between fish species, we must also take into account other various life forms that are commonly kept within a reef setting. Many anemone species are very capable of capturing and consuming fish. There are many coral species that have powerful stinging capabilities as well, while not usually a problem for most fish, it can become a health issue if a fish picks an area to spend the night that is within stinging reach of any number of corals. While the stings themselves may not kill the fish, they can open wounds which are then easily invaded by other pathogens such as bacteria. In larger tanks, this occurance of being stung is very rare since there is usually ample rock that provides caves / crevices well out of reach of corals that are usually placed on top of the rocks and towards the front of the aquarium. In small aquariums, the risk becomes greater as space becomes a premium.

A foxface that has slept a little too close to a coral. Which the fish should then be placed within a quarantine type tank and treated with an appropriate antibacterial medication to prevent infections. The landscape of the show aquarium should also be arranged to remove any corals or anemone that may pose such dangers to fish during the night.

3 - The vast majority of marine fish and invertebrates are wild caught. This means that they all come with a certain amount of baggage in the form of parasites, bacteria, viruses and the like, which all wild fish carry and live in balance with.
If we take all the above into consideration we can see that there is a recipe for disaster. If one buys an apparently perfectly healthy fish, if it is wild caught, one must assume that it will be carrying something somewhere and there is little that can be done about it, and the fish must be placed into quarantine for observation.
Certain treatments actually cause problems such as penicillins inducing blindness in clownfish, whilst many diseases have no known cure as yet. What we have got some control over is the environment within the aquarium. With correct husbandry techniques we can maintain the water quality at its optimum, feed the right foods and provide the correct social environment such that the fish are able to function at their best and will be able to control any unseen or unknown pathogens with their own immune systems.

Temperature. - This should be as close to the fishes' natural environment as possible. Fish (and invertebrates) are ectotherms reliant upon heat from their surroundings to support their metabolic processes. At low temperatures their immune systems are compromised, as are other processes such as their metabolism, digestion and drug absorption.Excessive high temperatures will reduce the oxygen holding capacity of the water and stress the fish.
When using treatments, it has been shown that lower temperatures (76-78) increases the effectiveness of anti-bacterial medications as well as slowing down the growth rate of bacteria as well as possibly slowing down the reproductive rate of some parasites. These lower temperatures should not be maintained any longer than necessary for treatment.

Salinity - The water surrounding a marine fish is more concentrated than the body fluids of the fish and so osmosis constantly draws water from the fish. This is why Hypo salinity during quarantine (only do so for fish only) reduces stress on fish since their bodies do not have to work as hard against osmotic pressures.
To prevent dehydration, saltwater fish must drink, with the salt that they imbibe being excreted via the mucus secreting glands of the skin,in the feces, but primarily from the kidneys and the gills. Sudden raising of the salinity will dramatically upset this delicate balance stressing or even killing the animal. Please DO NOT lower your aquarium's salinity level below normal in the mistaken belief that in doing so is good for the fish over the long term, it is harmful to the fish, causing kidney failure.

Oxygen level - The amount of dissolved oxygen is determined by the atmospheric pressure, the temperature and the salinity. Extreme temperature or salinity will reduce oxygen levels, often to dangerous levels.

pH - Saltwater has a pH of around 8.0 to 8.3, and has a significant intrinsic buffering capacity. However CO2 and other metabolic byproducts from the aquarium inhabitants will tend to reduce the pH.
This will to some extent be resisted by the normal buffering mechanisms but these can be exhausted allowing a rapid fall in pH. In tanks with a heavy algal growth, during the period of illumination the opposite may occur where all the available CO2 is utilized; bicarbonates are then used for photosynthesis resulting in the precipitation of carbonates and a rise in pH. This is why it is important to take your pH test at the same time of day/night each time you take a test. Running your sump's refuge area's light on an opposite cycle of the main tank can reduce this pH swing between daytime and night time.

Environmental Toxins - These include ammonia, nitrite, heavy metals, chlorine and chloramine. Ammonia is particularly important because at the high pH of marine aquaria it is mostly in the more toxic form of NH3.
Should one be correcting after a fall in pH, bear this in mind because as you raise the pH a significant amount of ammonia present will convert to the toxic NH3. Of the heavy metals, copper is probably the most important because it is toxic to invertebrates at low concentrations and to fish at higher concentrations, yet it is an important constituent of many off the shelf medications. Copper can bind to rock work in the aquarium, only to be slowly released at a later date, a fact which can result in invertebrate die-offs some time after copper containing medications were last used. Fortunately copper test kits are readily available.

Another area of concern is within the outer environment of the fish, namely the room / air that the aquarium is in. I have heard of many cases of having entire livestocks killed by the inadvertent use of any number of chemicals, solvents, smoke, aerosols and paint fumes either within the room, the house and even something as simple as the neighbor spraying his yard with pesticides, as well as having cleaning chemicals dropped into the aquarium while cleaning.
The top of an aquarium should never be used as a shelf to put your cleaning solvents, soaps, foods or additives on while you go about your chores. An accident waiting to happen is putting it mildly. You should take your aquarium into consideration when using such items.

Clownfish HyperMelanization - This seems to be a common occurance with clownfish that host corals. I assume that since clown fish's skin is adapted to dealing with the stinging power of anemones, the darkening of the skin is a response in trying to deal with the foreign mucous and stings of corals. I have never seen this condition become a problem for the fish and they seem to do just fine.

Nutrition - (Article has coral feeding needs also) Probably one of the biggest causes of problems developing within fish
It is extremely important to study the fish species you have in mind for your tank BEFORE you get it. If a fish is not receiving its proper food source(s) it is most likely not receiving its proper nutrition, which will weaken the fish thus making it much more susceptible to opportunistic diseases.
If a fish has a specific diet, such as algae, or copepods, you must ensure you can provide that diet well before you get the fish. For those fish that require live food but have been known to be trained to eat prepared foods, the training is much easier to accomplish within a quarantine type setting.
If you have its original food source available to supplement its feeding with during the training, in the event it does not take to the prepared foods it will not starve to death. Keep in mind also that in your attempts to feed a finicky eater, you may well also be polluting the tank causing water quality issues which can lead to another susceptibility issue. Frequent testing of the water should also be done.

Acclimation Stress - Often confused with an internal bacterial disease which appears very similar, the improper acclimation of marine fish can cause capillary congestion leading to the rupture of the capillarys through sudden exposure to higher salinity levels. This is most often seen with newly purchased fish that have not been acclimated very slowly, as in days long periods to higher salinity or when replacement water is above the aquarium's salinity when performing a large water change. As long as the fish is eating properly and it develops no other problems, it should heal in due time and recover. If the fish develops such red markings in the absence of salinity changes then I would suspect a bacterial infection due to poor water quality and the fish should be removed and treated by feeding it an anti-bacterial laced food while taking steps to get the organic levels of the aquarium under control.

EARLY WARNING INDICATORS - Most of us, once we have kept fish for awhile can tell when they are not feeling well, sadly though, by the time we do notice something is wrong, it may be too late since fish will appear or act as normal as possible for as long as possible, which I feel is a natural survival technique, since within the wild, any fish that shows any sign of weakness is quickly singled out for predation. Thankfully though, there are visible signs that we can watch for and take action before it does become too late.
A few things to be aware of or watch for:
- Loss of appetite, common among newly acquired fish due to stress, but if a normally active feeder stops, then it may be a sign of things to come.
- Discoloration , not to be confused with a fish's catatonic state in the dark or when frightened.
- Rubbing against objects, usually a first indication of a skin irritation / infestation.
- Rapid breathing , usually indicates an infestation of the gills which can inhibit oxygen exchange, it can also be water quality related, such as high ammonia levels or lack of aeration.
- Lack of movement, if the fish remains in one spot, resting on the bottom or hanging out near the surface can indicate an illness.
- Clamped fins, keeping its fins laid down or held closely to its body.
- Mucous or other obvious signs such as spots, specks or growths appearing on the skin or fins of the fish.
- Droppings that are out of the ordinary, undigested food, blood or otherwise abnormal in appearance.

A first-aid kit for saltwater aquariums
(provided by about.com)

For all of us who keep marine fish as pets, we should be prepared to be able to treat for any diseases and parasites that may be encountered. Finding out that your pet has a problem and having to wait for a store to open or a shipment to arrive can frequently cause the death of the fish.
Many pathogens are very quick acting and do not allow us to wait. As such, here is a basic first aid kit that we should all keep on hand and of course, stored safely just as you would any medication or hazardous chemical.
I would also like to suggest that you check with your local veterinarians if any of them have experience with treating fish, besides being able to do skin scrapings and culture for the results, thus giving you an accurate diagnosis, they can also prescribe medications not normally available through store outlets.

- A quarantine tank and all associated equipment standing by for immediate set up and use.
- Assorted measuring devices such as old unused, marked test kit vials, plastic syringes.
- A refractometer to accurately test the salinity since the use of hypo salinity is of great use to us. - Dipping containers / bowls.
- Copper test kits.
An assortment of medications to include but not limited to :
- Formalin 3 - Treats and cures a wide variety of bacterial, fungal and parasitic problems, for some parasites, such as brooklynella, this is the only effective treatment.
- Cupramine - a copper based product useful against marine ich and marine velvet.
- Maracyn 2 - an anti-bacterial product.
- Malachite green - effective anti fungal product.
- Methylene blue - useful with freshwater dips.
- Neomycin - anti bacterial.
- Pipezine - dewormer.

At the bottom of this page is a list of a wide range of medications available, having an assortment of products available on hand will increase your choices of treatment plans.

Please note: Be very careful with your medication / treatment plan as scaleless fish do not tolerate various chemicals.

Cryptocaryon irritans (Marine Ich) Usually billed as the marine equivalent of white spot, the parasite usually presents itself initially by causing a loss of appetite, some skin irritation and minor respiratory distress.
Closer investigation will reveal pinhead-sized white to gray nodules. The parasite causes excessive irritation resulting in reactionary growth of the skin surface, these growths are what you see as very small white spots.The parasite is highly infectious and often fatal within three to five days.
The life cycle is complex and will continue in the aquarium until all the fish are either dead or develop a partial immunity. Do not confuse this parasite with the brooklynella parasite which may cause similar skin reactions seen after the first indicators of brooklynella, which are cloudy eyes and excessive skin mucus being produced. Please see the link provided.

Amyloodinium Also known as Velvet. This is a rapidly progressing disease which starts off at the gills and so shows initially as respiratory distress but will then spread out across the skin.
Signs include respiratory distress, skin rubbing and erratic swimming. Without treatment death can occur within two days of respiratory signs. This is an additional link concerning identification and life cycle. Hypo Salinity treatment is not effective.

Turbellarian or "black ich" is caused by one or more genus of flatworm, with distinct life cycles as you see with the true marine ich. The only obvious signs of this parasite are the dark spots which is a skin reaction of the fish being attacked by the parasite and is not the actual parasite. As you can see in the below photo, this flatworm parasite can also infest other invertebrates such as this yellow sea cucumber. Yet another very good reason to quarantine everything before it goes into your main aquarium system.

Brooklynella - Similar in appearance to Uronema, these protozoa seem to be increasing in importance. The infections are initially confined to the gills but eventually will spread causing tissue irritation and skin slough producing ulcers.
Fish become lethargic and secrete excess mucus. Death can occur within twelve hours from toxins released by the protozoa. First indicators can include heavy breathing, cloudy eyes, excessive mucus and Ich like lesions. This parasite must be dealt with very quickly!!

Cryptosporidium nasoris is a coccidian protozoan which attach to the lining of the guts of fish. Hoover et al. (1981) described this species from 8-cm long naso-tang, Nasolituratus Bloch & Schneider originating from a pet store in the USA and kept within a marine aquarium.
Histological examination and electron microscopy of intestinal mucosae revealed organisms resembling members of the genus Cryptosporidium. Infected fish show emaciation, loss of appetite, regurgitation and droppings with undigested food in them.
Other coccidia can invade the gall bladder, liver kidneys and even the gonads, effectively neutering the fish. Over sixty species of myxosporideal protozoa have been reported in marine fish. One particular one, Glugea heraldi, forms whitish cysts just under the skin on Atlantic seahorses.

Myxobolus parasites are another common infestation of wild caught marines. Indeed most tropical marines harbor Ceratomyxa, Myxidium or Leptotheca in their gallbladders. Septemcapsula plotosi and M. Cerebralis have been found to infect the nervous tissue of fish causing the fish to whirl before death. There is no known cure for this problem.

Uronema Marinum - U. marinum are single-celled, microscopic, ciliated, opportunistic invaders that normally feed on bacteria in the aquatic habitat.
They are constantly in an energy acquisition phase (always looking for food. When the fishes immune system is stressed, U. marinum will attack the fish, invading muscles and internal organs, eating red blood cells and other cells. Uncontrollable or recurrent infestations are typically indicative of underlying problems such as introduction of new fish, overcrowding, and poor water quality.
Life cycle. This takes place by simple mitotic division, but there seems to be quite a body of evidence that in marine Aquariums at least, that high organic loads appear to favor the reproduction of the ciliate.
The below picture is a necrotic wound caused by this parasite. The parasite can be confused for brooklynella which if treated is not a problem in misidentification since the usual formalin treatment will destroy both types of parasites.
This parasite is just as deadly and as quick acting as brooklynella and will remain viable for some time even after the fish has died.

Most bacterial diseases of marine fish are secondary opportunist infections, secondary to such stress as poor water conditions, transportation and wounds.

Internal Bacterial Infections - Usually shows itself as bloody patches or streaks visible in the fish, this type of infection requires the fish to be removed to a quarantine tank for treatment of both its water and its food to ensure a speedy recovery. Please DO NOT attempt to perform treatments in the main tank.
While being treated within the quarantine tank, feed the fish a medicated antibacterial fish food such as Gel Tec. For an initial treatment plan, I would at first, go with a medication that targets gram-negative bacteria as these are the most commonly experienced problems. Such medications include Maracyn 2 or a sulfa based medication.
If after the prescribed treatment period, it is found to be ineffective, I would then switch to a gram-negative medication such as Erythromycin. Please note that it is extremely important that you perform each and every treatment period to the end of its prescribed length of time. If not, by subjecting bacteria to short dosage periods, you could be creating a medication resistant strain of bacteria, which would be even more difficult to eradicate. Also, never mix any medications regardless of any manufacturers claims of being able to do so.
If you do find that you need to change to a different medication, do a partial water change and run carbon to remove any traces of the previous medicine before adding a different one. Even if the fish looks much better, never stop the treatment until the completion of the prescribed treatment time.

Fin Rot. Evident when the fins show degeneration and start to look ragged in appearance. The most common cause of fin rot is physical abuse, followed closely by poor water quality.
The bacteria responsible for further fin loss is a gram negative bacteria and can be treated in a quarantine tank with an appropriate anti-bacterial medication.

Pop Eye /Cloudy Eye. A very obvious swelling and / or cloudiness of the eyes, this is most often caused by poor water quality or physical damage or abrasion to the eye of which secondary bacterial infections can take advantage of.
This is another gram negative bacteria responsible for this condition and can be treated in a quarantine tank with an appropriate anti-bacterial medication. As with all fish problems, stress is the leading cause of illness, usually water quality can be blamed. In good water quality, this condition most always disappears on it own without further treatment. For extreme cases, as shown in the photo, a medicated treatment would be advised.

Treatment per Dr. A.J. Meyer - Using a small container, place 4 liters of tank water and add 1 ml of a 10% solution of Baytril oral solution (enrofloxacin). Place the fish in for 60 minutes at a time once daily with an airstone and repeat for 5 consecutive days. The same water can be re-used each of the five days. This medication or solution should be available by prescription from your local Vet.

Photo Credit : Kelly Jedlicki Photo Credit : Kelly Jedlicki Photo Credit : Chuck Purdy

Vibriosis. A rapidly progressing septicaemic infection characterized by skin hemorrhages, lethargy, anorexia and the eventual formation of deep skin and muscle ulceration.
Definitive diagnosis and treatment is based upon culture and sensitivity tests. A commercial vaccine, produced for salmonids, is available and would be worth considering if Vibrio became a recurring problem.

Pasteurellosis. This presents as a haemorrhagic septicemia similar to Vibriosis. Should the fish survive this then grayish-white granulomatous lesions form in the spleen, liver and kidneys - a condition known as pseudo tuberculosis. Treatment is with appropriate antibiotics.

Fish Tuberculosis. Very common in marine fish. Granulomatous lesions due to the mycobacteria can affect any organ and so the fish may present with emaciation, ulceration, anorexia, loss of color, respiratory distress or exophthalmia.
Laboratory diagnosis is essential especially because of the potential risk to the aquarist. Other bacteria may occasionally be isolated including Edwardsiella, Aeromonas, Pseudomonas, Streptococcus, Flexibacter or even Eubacterium tarantellus - this latter bacterium affects the central nervous system causing altered pigmentation and swimming patterns.

External Lesions Note TB nodules on the liver as well as worms
Photo Credit : Kelly Jedlicki

External (Gas?) Bubble Disease - I believe these formations can be caused by two distinct, separate aquarium conditions. In the below photos, the bubble formations appear to be fluid filled, in this case, a bacterial infection would be suspect.
Just as with "pop eye", an aquarium with high organic levels, or the use of crushed coral as a substrate provides the conditions for bacterial growth, in such high numbers, the bacteria can quickly overwhelm the fishes immune system or invade the fishes protective mucus coating.
This condition should see the fish removed to a quarantine tank for treatment with an antibiotic while the aquarium receives a filtration or substrate make over. Increased water changes will help in the short term, but one must look at the entire system and the amounts of food being fed to the system.

If the bubble formations appear to be shiny, then most likely there is an actual gas involved. This can occur when the total dissolved gases within the water reach a super saturation level. Heavily aerating the water can lead to conditions where the water holds a great deal of dissolved gases which then comes out of solution within the fish and forms actual gas bubbles, some of which will appear externally on the fish as well as the fish having internal formations as well.
Higher temperatures or a sudden increase in temperature can bring gases out of solution. To cure this problem, you may want to reduce or slow down the amount of aeration the tank is receiving and ensure the water temperature maintains within normal parameters.

Photo by Matt Pedersen

Photos provided by Matt Pedersen of MarineBreeder.org

MYCOBACTERIOSIS - Emaciated appearance along the narrow, dorsal edge. A sunken belly becomes noticeable, although bloating (ascites) may also occur, due to fluid accumulation in the body cavity.
Unilateral or bilateral exopthalmia (Popeye) are common symptoms, as well as lifted scales, pale coloration, and in advanced, chronic cases, spinal curvature. All this soon leads to a loss of appetite, jerky swimming, greatly reduced reactions and reflexes.
Ultimately, the affected fish becomes lethargic, seeking the corners of the aquarium, appearing to want to remain apart from it's tank-mates until it dies. Quoted from Mr. Lance Ichinotsubo.
As is the case with any of the bacteria, they are opportunistic and will take advantage of what other diseases have done to the fish causing secondary infections. The below photos show this bacterial strain having done so as confirmed by laboratory identification as being a Mycobacterium.

Photo submitted by Morgan

Mycobacterium marinum - This bacterial strain is a very real and present danger to ourselves and has the greatest potential for human contraction with a disease associated with their aquarium.

SAPROLEGNIA - (FUNGUS) - Fungal disease in tropical fishes is associated with adverse environmental conditions. Infection, whether occurring in isolated individuals or in epidemic proportions, is preceded by some environmental stress that disrupts the normal host defenses.
Most of these infections are attributed to members of the genus Saprolegnia. These organisms, considered to be saprophytic "water molds," are a normal, ubiquitous component of aquatic ecosystems. Saprophytes live off of decaying organic material and are essential for recycling nutrients back into the environment.
If you have ever seen a piece of fish food left in the aquarium and was covered in what looks like cotton, those are all fungus filaments doing their job of breaking down organics, the problem is when they start trying to break down your living fish and can also appear as cottony growths on the fish as well.
Fungal infections can be unseen killers if the gills are infected, which may happen if another pathogen such as a parasite has damaged the gills allowing the fungus to gain access.

Individual fungal filaments Severe case on Tail area

Viruses appear to be very common in fish although not all are associated with disease. Treatment is rarely practical aside from provision of optimum conditions to allow the fishes' own immune system to deal with the infection.

Lymphocyctis virus. This virus induces massive cells to form which appear grossly as grayish-white masses on the fins and gills. Such abnormal cells may also be found in the muscle and body cavity.
May be confused with chlamydia infections (epitheliocystis), parasitic cysts or sarcomas. Infections are usually self-limiting and may spontaneously clear of their own accord.

Cell Masses on body Note fungus like appearance on fins

Lymphocyctis on a cowfish

Tang Fingerprint Disease. Oval fingerprint-like areas of discoloration occur on the sides of tangs and surgeon fish. Fish feed well at first but deaths can occur. Given ideal conditions the disease appears to be self-limiting.
Initially thought to be a result of traumatic damage, microscopic investigations failed to confirm this; it is believed to be viral although no viral particles have yet to be identified.

Infectious Pancreatic Necrosis Virus. Usually considered a disease of salmonids IPN virus (or to be precise, a virus indistinguishable from IPN) has caused disease in over twenty different species of tropical marine fish.
In an outbreak the fish lost appetite, became lethargic and eventually disorientated. Some became ascitic and hemorrhages at the base of the fins were common. Unlike in salmon there was none of the classic necrosis of the pancreas.

Angelfish Encephalitis. Seen in French and gray angelfish, affected fish become lethargic, lose their appetite and secrete excess mucus. Eventually they lose their balance and die. There is no known treatment or control measures.

HLLE or "head,lateral line erosion" Head and lateral line erosions seen in marine fish. Associated with an aquariovirus. Usually starts out as visible pitting (holes) around the eyes and along the lateral line. Better water quality and diet usually allow the fish to fully recover.

Turbellarian flatworms have caused skin damage and eventual deaths in yellow tangs. Other species affected included surgeon fish, angelfish, butterfly fish, parrot fish and wrasse. Outbreaks are associated with poor husbandry and high levels of organic matter in the aquarium.

Monogenean Parasites are better known as flukes or flatworms, which live as parasites on fish usually infesting the gill areas first. Being monogenean means that they have one direct life cycle and do not need an intermediate host to multiply. These parasites are usually transmitted by direct contact between fish.
Long term treatment methods such as formalin baths will be needed since the eggs of these parasites can survive initial one time treatments. Most are commonly located on the skin and in gill chambers and more rarely in the mouth and body cavities. They use hook attachments to grip the epidermis whilst feeding on the skin and gill tissue; this causes only superficial damage.
More importantly they can cause epidermal ulceration after heavy feeding thus in numerous quantities can in fact cause heavy damage. They are also thought to transmit other pathogens. Treatment should include antibacterial medications to prevent secondary infections as shown in the fish below.

Photo by Rob Hasler

Monogenean Flukes, Please see the above link for more details and treatment options.

MONOGENETIC TREMATODES (Monogenetic = direct life cycle) of the genera Gyrodactylus and Benedinia occasionally cause problems.Often near the eyes or gills, affected fish show signs of heavy respiration and scratch against objects in the aquarium.
Some fish may hover in the water with their fins clamped tight against their body. The eyes may be inflamed - the trematode Neobenedenia can cause corneal ulceration with eventual functional loss of the eye.
Diseases caused by tapeworms and nematodes are relatively rare in aquaria, because in the majority of cases an intermediate host(s) is required in the worm's life cycle - a stage from which the fish will be isolated in the aquarium. Encysted stages or living worms may be found in fish. Some species may have an ability to switch to a direct life cycle - for instance Spirocamallanus which has been found in 16 species of tropical marine fish in Hawaiian waters, can prove to be a problem in aquarium fishes.

Heavy Trematode Infestation

NEMATODES or internal roundworms, while somewhat rare in captive bred fish since most worms need an intermediate host for the life cycle, the same can not be said of wild caught specimens, which in our hobby makes up the bulk of our available species.
Our marine tropicals are most likely able to bring home a variety of problems with them. A medicated fish food should be used to administer the medication. As a suggestion, Hikari makes a product called Prazi-Pro in which the active ingredient is Praziquantel, also, Gel-Tek makes a product called Ultra Cure PX, which contains metronidazole, flubenol and praziquantel, all of which are de-wormers.

Besides a "bloated" belly, having the fish discharge a "stringy" appearing excrement is usually the only first indicator that we will have of an internal roundworm problem. Although such a "stringy" appearance may also only be an indication that the fish needs a more meatier diet as well.
The lack of any truly visible signs of such an infestation, is a very good reason to assume that all newly purchased / caught fish are infested with worms and should be medicated as such while they are in their mandatory six week quarantine period.

The severity of nematode infestation in fish will vary depending upon the life stage, species, and number of nematodes present; the age and species of infected fish; and the sites of infection.
Even though adult nematodes are typically found in fish intestinal tracts, adult and other life stages can be found in almost any organ, but they are most commonly present in muscle, the liver, and tissues surrounding the internal organs.
Visible signs of infection may include hemorrhaging, cysts or granuloma formation (a granuloma is a reaction by immune cells in which the cells try to “wall off” some foreign body, in this case, the worm. Granulomas formed around worms can look like little brown “rock-like” areas in the shape of the worm, but will be surrounded by a distinct clear area at their very edge), external lumps or nodules, inflammation, and necrosis (presence of dead and dying tissue.
Adult nematodes in the intestinal tract damage its lining and rob the fish of nutrients, causing a "wasting" effect. These are the only types of roundworms that we can treat for, any worms outside of the intestinal tract are for all purposes, untreatable.
Feeding our fish live foods or fresh seafood can transfer worms to our fish, as such, I freeze all fresh foods to ensure any and all worms are killed, I would also avoid feeding live food such as other fish to our larger predatory fish.
For treatment, a medicated food such as an anti-parasitic food by Jungle that contains Praziquantel, levamisole and metrodinazole. The first two medications will deworm and the last one will work against intestinal protozoans. Another product call Ultra Cure PX by Gel-Tek can also be used.

Photo Credit : Kelly Jedlicki

Quote Leslie Harris "An internal copepod parasite called Serpentisaccus magnificae which lives on the orange fire fish Nemateleotris magnificae. What you have appears to be the same or a similar parasite. The genus name of the parasite - Serpentisaccus - describes the 2 long curly egg sacs. The rest of the body is deeply embedded in the fish's body. Even if you pull off the egg strings, unless the parasite is so damaged that it dies it will just grow new egg sacs. This type of parasite usually doesn't kill the fish and if the fish is healthy it should be able to tolerate the parasite. The life cycle of this parasite isn't known. Similar copepods go through up to 11 developmental stages starting with planktonic forms before they become the final adult form. Some species require an intermediate host like a snail but others don't; once they stop being planktonic they find a host fish to live on. Without knowing the life cycle it's impossible to predict if the eggs can survive long enough to become additional parasites. Hopefully they will be eaten or removed through your tank's filtration. these parasites tend to be very specific about which fish they live on so it's unlikely that they would attach to any other fish in your tank." Unquote.

Below : Various Copepod and Isopod parasites

Caligidae (copepod) Hatschekiidae (copepod) Lernanthropidae (copepod)

PARASITIC CRUSTACEAN IDENTIFICATION
You will need the Adobe Reader for this link, download it HERE

This group includes some "old favorites" such as the fish louse Argulus sp. which may occasionally turn up. Parasitic copepods may be seen, often near the eyes or gills. The isopod parasite Icthyotaces pteroisicola has been reported to cause marked skin swellings on the lion fish Pterois lunulata, each swelling acting as a protective sac for one parasite. For large obvious Isopods attached to the fish as shown above, manual removal would be best, which can be done with a pair of tweezers or by placing the fish in a dip solution.

Disease Terminology and Treatment Drugs

When it comes to curing a fish, there are only two methods available to us, either Chemotherapy or Environmental, both of which have their place, but never within our tanks.
All treatments must be performed outside of the main tank within a Quarantine Tank. As long as there are hobbyist who insist on rushing home with their new purchases and putting them directly into the main tank, then there will always be disease and parasite problems.
All large aquariums throughout the world all have strict quarantine procedures in place for a reason. It works!.
Besides using a medication for a treatment, you should also provide pristine water conditions to reduce any stress on the fish as well as not giving the pathogen its suitable environment (organic laden).
Keeping the tank's temperature on the lower end (low to mid 70's) will hinder the growth of most pathogens and may allow medications to be more effective. Also keeping the salinity lower (SG 1.018) helps with oxygenation as many antibiotics "work" better in lower salinities as well.
Stress reduction is very important at this point as stress will increase the fish's metabolic rate which increases the oxygen need, which further increases the metabolic rate, a very vicious circle.

ALL TREATMENT PLANS MUST BE CARRIED THROUGH TO THE END OF THEIR SUGGESTED LENGTH OF TREATMENT, EVEN IF THE FISH IS LOOKING BETTER, CONTINUE TREATMENT. TO CUT THE TREATMENT SHORT ONLY INVITES THE CREATION OF MEDICINE RESISTANT PATHOGENS.

A Note on Scaleless Fish - Any medication used in the treatment of parasites, such as formalin and copper must be used at half the recommended dosage, if you see the fish having problems during such treatments, a water change will be required to reduce the medication levels and another treatment plan should be considered.
For Mandarins - Which are notably slimy fish that are not as susceptible to external parasite infestations as other fish may be. However, they are not immune, and are overly sensitive to copper compounds, other metal-based and formalin containing medications. They are best treated through environmental manipulation, such as hyposalinity.

DIPS / BATHS - Overall article on how to and what to use per a given infection / infestation.

HYPO SALINITY : The lowering of the water's salinity down to 1.009 will reduce stress on fish and kill some types of parasites, most notably, Marine Ich. This treatment requires accurate salinity testing, which a refractometer will do. The usual hydrometers are not accurate enough to ensure proper salinity levels are achieved. I strongly urge using this treatment during all quarantine periods for new arrivals of fish.
Test Kits - If you test your water for calcium or magnesium at hyposaline levels you will get a much lowered test result. Since test kits are affected by temperature and salinity levels the following formula will take hyposaline into consideration. Temperature range 74-86f .
For calcium tests - Take your current readings of your SG and subtract it from a base of 1.025 if your temp is below 80 and 1.023 if your temp is above 80 and is a multiplier of 9.632 then add that number to your calcium test results that the kits gives you. Example - 1.023 -1.009 = .014x9.632 = 0.134848 round to135, Current reading is 230+135=365
For magnesium tests - Use a multiplier of 2.741 but subtract that number from your current test as it will read slightly higher than normal the fresher the water gets.

FORMALDEHYDE (Formalin - 3% formaldehyde) - A very effective treatment for parasites. Extreme care must be used when handling this chemical. Please take the time to make sure you fully understand its dangers and correct usage.
DOSAGE: 1 teaspoon of a 3% solution per 10 gallons every other day for 10 days. Combines well with malachite green.

Note: For those of you who live where Formalin is controlled or restricted, there is another product called ProForm C , which contains both malachyte green and formalin that should be available to you.

COPPER BASED Medications - Another effective treatment for parasites, and as with all chemical treatments, care must be taken with its use, accurate dosing is very important and must be done outside of the main tank. A chelated copper is considered to be of a less hazard to the fish, but may not be as effective against the parasites. For unknown parasites, I would use this method since it will kill all external species of parasites, with the exception of Brooklynella, then formalin dips would be advised. I personally would recommend Cupramine be used.
DOSAGE: Treat according to your solution to bring your copper level to .15 -.20 ppm. Sequestered Copper (often called chelated, but that is incorrect, chelated means inactivated) sulfate works best (citric acid help achieve this). Soluble copper salts work well in freshwater only. Do use with snails and other invertebrates, do not use in reef aquariums, and note; when uses as an algaecide, the copper is absorbed by the algae then released when it dies. Removal of sequestered copper can be difficult, only EDTA (Ethylene Diamine Tetra Acidic Acid) and water changes remove it, NOT carbon.

FRESHWATER DIPS - While I do not feel that a freshwater dip is a cure, since not all parasites will be removed, and can be very stressful for the fish, but this procedure is helpful if the fish is heavily infested and needs some immediate relief, by reducing the number of attached parasites, it may help other treatment methods be more effective.

ERYTHROMYCIN - Effective against most gram-positive and some gram negative bacteria and fungus. It is also used to destroy cyanobacteria but does have its risks when used in a reef aquarium.
DOSAGE: 250- 500 mg per 20 gallons every 24 hours with a 25% water change before each treatment. Treat for 10 days.

METRONIDAZOLE - A very effective treatment for Internal Protozoal infections.
DOSAGE: 250-500 mg per 20 gallons. Treat every 24 hours with a 25% water change before each treatment. Treat for 10 days.

PIPERAZINE - Sold as Pipezine and is useful for the treatment of internal nematodes (roundworms).

MALACHITE GREEN - Seems to be a dangerous compound to use but has been shown to be effective against a variety of problems, most commonly as a treatment for Fungal infections.
DOSAGE: 1 teaspoon of a 0.038% solution per 10 gallons every other day for 10-14 days. Or 1 drop of .50% solution per gallon every other day for 10- 14 days. 25% water changes are recommended before each dose. Use half dose for scale-less and delicate fish such as Clown Loaches and Neon Tetras. Double dose for marine aquariums. Note; malachite green is more toxic at higher ph.

NEOMYCIN SULFATE - An effective treatment for bacterial infections. NEVER mix with copper sulfate!
DOSAGE: 250 mg per 10 gallons of water. Treat every 24 hours with a 25% water change before each treatment. Treat for 10 days. For tuberculosis, use for up to 30 days.

METHYLENE BLUE - Commonly used as a "cure all" for bacterial infections.
DOSAGE: 1 teaspoon of a zinc free 2.303% solution per 10 gallons every other day for 10 days with water changes before each treatment. BEST USED IN A QUARANTINE TANK. Methylene blue can destroy nitrifying bacteria and plants in the display aquarium.

MINOCYCLINE - Sold as Maracyn 2 , Very effective against bacterial infections, if used at double the recommended dosage. Side note: This medication is also administered to us humans since there is a bacterial infection that we can catch from our fish tanks! Human Infections

NITROFURAZONE - Sold as Furacyn, Effective against bacterial infections.
DOSAGE: 250- 500 mg per 20 gallons. Treat every 24 hours with a 50% water change before each treatment. Treat for 10 days.

KANAMYCN SULFATE - Sold as Kanacyn, Effective against bacterial infections.

OCTOZIN - Useful for internal parasites.

PRAZIQUANTEL - Sold as Prazipro and Droncit,Effective against Trematodes. While this is a very difficult problem to diagnose, it is important to note that with Trematodes, there are two distinct forms of concern for us, which involves their life cycles, there are digenetic trematodes which require two or more other life forms that they must pass through before ending up on our fish, since those other life forms are not present in our tanks, this problem will just die off on its own. The type of trematode that is of concern for us are the mono genetic types that have only one host needed (our fish). If this medication is administered via bath it will not be as effective on internal parasites as administering via food. Can be obtained on line: Nationalfishpharm.com or through a vet.

ACRIFLAVINE - Effective against the parasite Amyloodinium.

SULFASOXAZOLE - Effective against bacterial infections.

TRIPLE SULFA (Sulfamerazine, Sulfamethazine, Sulfathiazole) - Treatment of gram-negative bacterial infections, fin and tail rot and mouth fungus.
DOSAGE: 250 mg per 10 gallons every 24 hours with a 25% water change before each treatment. Treat for a minimum of 10 days.

"Natural" Treatments:

PIMAFIX - Effective against cotton like fungal infections as well as external and internal bacterial infections. There is debate on such medications amongst the hobby, some are against its use while other hobbyists have noted very good results with this product if used in conjunction with Melafix. A word of caution with its use, there has been observations that fish may experience oxygen deprivation / suffocation. As such, increased aeration should be used as well as monitoring the fish closely.

GARLIC- In my corrected opinion, while garlic use is still somewhat of a controversial additive, it does perform as a mild anti-helminth (dewormer) and does have some anti-bacterial properties, but should be used with more conventional treatments.

BETA GLUCAN - "Beta glucan works as a biological defense modifier. It activates the immune system by stimulating receptors on macrophages that cause them to react as if a fungus is attacking the body." In other words, this is a great way to help the fish help itself, supplementing this product to the fish food will increase its own immune system and may just save you a few trips to the fish pharmacy.

Please take a moment and consider supporting any one of the projects listed within. Thank you.

Visitors to this Page since 24 Jan. 2008