Slugs and Nudibranch

Far to often we walk into a fish shop and see a tank of wildly colored nudibranchs usualy listed as "Assorted Beautifull Slugs" but asked what species they are, you will most likely get a blank look or a flat out lie. They will also tell you that they are eating just fine because a slug is crawling over the top of some fish flakes. Nudibranch and most slugs/flatworms are highly specialized feeders, usualy of corals, sponges or tunicates. Not something we would be able to, or want to provide within our aquariums.
I strongly recommend that you do not buy them unless you know exactly what species you are buying and what that species feeds upon. If we stop buying them, then so will the fish stores. One other point a fish shop will not likely know or remember to mention is that the bright coloration that we find so beautiful is actualy a visual warning to potential predators that they are very toxic to eat, which makes sense for a slow moving soft bodied creature that lives out in the open to have a defense against being attacked, a very toxic defense. To have one die of starvation within an aquarium, it could release those very toxins upon the death of the slug. Most likely killing your fish in short order.

Nudibranchs: Beautifull but Dangerous Marine Creatures - "Most sea slugs are either very difficult or impossible to keep in small private aquariums. They are very delicate to ship and sensitive to acclimation. Their diets are very specific, and, as much species are toxics, after dying, there is a very real danger that, due to their decomposition, some toxic compounds could be released into the aquarium and disturb or even kill other organisms."

Melibe Fimbriata - This one was a great "hitch hiking" find for me within my system and is one of the few nudibranch that one could consider to be reef safe and able to survive our systems as long as any pump intakes are covered. A great little filter feeding Nudibranch also capable of consuming copepods if they happen to sweep them up during their travels.

Photo by Charles Raabe

Feeding on Copepods
Photo by Charles Raabe

Anemone predation and reproduction of Hitch hiking Aeolid Nudibranchs - " Virtually all nudibranchs have specialized mouth parts and digestive tracts. This means that they consume only one or a few very closely-related foods, typically sponges or other sessile invertebrates that cannot be supplied adequately in aquariums. "

Naked Gills on Snails - " the Order Nudibranchia is huge, with several thousand species having been scientifically described, and more being found regularly that are not yet described. "

Aeolid Nudibranch in the Reef Aquarium - " Having a color pattern of any sort implies the production, utilization and storage of pigments. Pigments are often complicated chemicals that may be metabolically "expensive" to produce and maintain. Thus, there is a cost of having "color" of any sort, but having a protective coloration is better than being dinner. "