Advice on keeping nudibranchs in aquariums

Dear Phanor,
Colombia, with coasts on both sides of the Panama Isthmus must be a very interesting place to study marine biology. I don't know of any books specifically on that fauna but I suspect you should have a look at the books on the nudibranch fauna of North America, such as Dave Behrens' Pacific Coast Nudibranchs (2nd Edition, 1991) which covers the fauna from Alaska to Baja California.

Also have a look at the sections on Pan American Nudibranchs & Pacific Coast Nudibranchs in Mike Miller's Slug Site at http://slugsite.tierranet.com/

My advice though, is not to choose the nudibranch you would like to put in your tank, before you actually see what nudibranchs you can easily find. Unfortunately even the 'most common' nudibranchs can be impossible to find when you actually want one. I would think that part of your project is to do some research on the natural history of the animals you are keeping in your aquarium, and finding out how to keep them alive would be good start.

What I would suggest is you go and look for some common nudibranchs, either intertidally or subtidally, remembering that you may need to replace your animals if they die. You are almost certainly going to have to replace their food many times, if you are going to keep them alive.

You will see from the Sea Slug Forum, and other sources, that nudibranchs all have very specific diets and most feed on other animals that are difficult to keep alive in aquaria. If the animal you choose feeds on a sponge, try and find small colonies of the sponge on removable rocks which can be placed in the aquarium without damage to the colony. You will need to check the colony regularly and remove it if it looks unhealthy so it doesn't contaminate the water. Alternatively you are going to have to find a nudibranch which feeds on a sponge species that you can easily collect every day, or so, to replace the one in the aquarium. I had a student working on a chromdorid nudibranch with direct developing juveniles, and he had to collect a sponge colony daily and break it into pieces to feed his juveniles. It is possible, but time consuming.

The same applies to nudibranchs feeding on hydroids, sea anemones, soft corals etc. Some anemone-feeding nudibranchs are quite good in aquaria because they feed on a variety of anemones, and anemones are relatively easy to keep in aquaria. You may also be lucky and find an aeolid like Hermissenda crassicornis which is a more generalist feeder and can be fed artificially in aquaria.

I would think the first thing you should do then, is find somewhere you can get to easily, as you may have to return many times, and then choose some nudibranchs that are relatively easy to find there. Hopefully they will be on or near some possible food so you can make an informed guess at what they eat.

If you find some nudibranchs you think could be easy to keep alive, you could then send some photos to the Forum and we could see if anyone can help you with information on their identity and natural history. We probably won't know anything about the natural history of the animals you find, but we can probably give you some clues on what they are likely to do or feed on. In that way you will be able to do some original research which will of interest to us all.

Best wishes, and good luck,
Bill Rudman.