By Charles & Linda Raabe
Mactan Island, The Philippines


    Every one of us who has ever bought live rock or sand has at one time or another stood in front of our tanks wondering what that thing is that just crawled out of the rocks. Usually our first thought is of concern if that "thing" will eat our fish or corals.
  Thankfully most of what does hitch hike in with the rocks are harmless and add to the diversity of life within our aquariums. Yet there are some creatures that just do not belong in an enclosed system and can become a problem. Since live rock can and does provide homes for multitudes of various life forms, knowing each species at a glance is far beyond most of us, of course one must get a correct identification in order to determine if it is considered harmless or not. Hopefully these pages and others will help you to determine the suitability of such finds. If you find an identification impossible to locate, then common sense will have to suffice, if the animal in question is obviously behaving badly, then it should be removed.

A special thanks to Dr. Ron Shimek , Leslie Harris and Susan Spark for their invaluable help with the identifications made and to David Lee for providing the means in which to provide better photo quality. Your generosity will be greatly appreciated for many years to come.

A Reef Aquarium Clean Up Crew
How to select the proper animals

>Your best source for proper clean up crews!

     The most commonly found shrimp species within live rock are the mantis and pistol types. I would only consider the mantis to be non-reef safe. Other types of shrimp are usually carried in as commensals of corals species or hiding within the rock's crevices posing no real threat  to other livestock being kept

     Thankfully there has been enough identifications done, in large part due to Leslie Harris, that with the multitudes of worms species it has become easier to identify most worm family & genus groups. For identification purposes, the head structures are most important.

   With the exception of the commensal crabs I do not introduce or allow to remain, any of the crabs found hitch hiking in with live rock. Such free ranging crabs including the hermits are just far too destructive to the life within our reef aquariums.

     When snails are found as hitch hikers there is a very good chance that it may be a predatory species. Identification may be difficult if one does not know the features to examine or does not have reliable reference material.  This section also includes some nudibranch and sea slug species.

   From copepods to reproductive worm segments, there are few aquariums that one can not sit in front of at night with a flashlight and a magnifying glass and not discover a whole new tiny world if one takes the time to look, closely.  Nutritional content and how to catch your own zooplankton from the wild.

    It is very common for an established reef tank with live rock to have numerous sponge species just appear out of seemingly no where. While some types will persist and remain, far to often you will see a sudden growth of sponge which will linger for a few weeks and then disappear as suddenly as it appeared. 

       From Foraminiferans, Sea Spiders, Jellyfish, Ctenophors to Synaptids. This page includes some of the more unusual, yet still common finds within our systems.

     Thankfully starfish and sea urchins are fairly obvious as to what they are.  The juveniles are most likely to be encountered as hitch hikers.  I do not recommend purposely keeping starfish and sea urchins as they either do not survive our systems or become dangerous to other aquarium inhabitants along with growing too large for most aquarium systems.

     It would be extremely rare to have a commonly kept species appear as a hitch hiker. The vast majority of  sea anemones found will become a threat either due to their rapid growth and spread or by their moving through the aquarium and stinging sessile invertebrates that can not get out of their way.

     It is not uncommon to find corals or polyps growing upon live rock, some of which are common and easily identified. Those I will leave to the coral pages and only high light the most commonly found species.

Click to view    There are numerous other organisms that may appear within our systems which tend to become problematic as the aquarium conditions that favored their appearance most always favors their becoming a pest.

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