Nudibranch... ID, Behavior  2/23/08 Hi, <Hello Tina, Mich here.> I found a critter in my tank. At first I thought a piece of my pulsating xenia had broke off and stuck on the tank glass. Later I noticed it had moved. <Just as an FYI, Xenia can move... just very, very slowly.> Immediately I captured it and placed in a glass tumbler. It was sliding about the tumbler like a slug so as you do I went on your web site to ID my critter. <Excellent.> I have come to the conclusion it is a Nudibranch (Bornella calcarata) was the picture that matched mine the most as listed on page 2 Nudibranch). <Nudibranchs be a challenge to ID, even for some of the most experienced... Please see here heehee! http://www.seaslugforum.net/display.cfm?id=8163 > But before get rid of this coral-eating critter <Often are but not always, but their diets are usually very specific, and typically difficult if not impossible to provide in captivity.> I would like clarification of what it is as all of a sudden it stopped sliding around the tumbler, it's body turned flat and double its normal width and started to swim i.e. it's body kept bending in half and straighten again sort of flapping kind of like a caterpillar movement and it was swimming quite fast. <Nudibranchs can swim. Here is some video of a Spanish Dancer (Hexabranchus sanguineus) http://www.oceanfootage.com/stockfootage/Spanish_Dancer/owner%3Dkandykendall > I read on Nudibranch behaviour but this wasn't mentioned. I don't want to get rid of it if it is going to do no harm. <Really depends on what it is, a picture could help with identification, but I'm sad to say it will likely face an untimely death in captivity due to lack of nutritional resources.> Look forward for your reply Tina .x <Cheers, Mich>

Lettuce Nudibranchs... beh. -- 04/30/07 Hello distinguished experts <Heeee! Am more extinguished myself> I met at least a couple of you at Saltwater U in Atlanta Last year. Look forward to hearing you speak again this year! <Geez, gots to get hot on my pitch for next weekend> My question may seem odd; if so have laugh at my expense. You won't be the first. Is there any history of a Lettuce Nudibranch moving into a Astrea or Trochus shell? <For a short while, sure> My research suggests both would have an opercula. <Mmm, no> Our snail does not have one. He simply retreats as far as he can leaving flesh exposed. When placed upside down in the sand he spirals partially out to get a foot hold then rights himself. Hasn't yet fully come out of the shell but what we can see of his body doesn't look the other snails in the tank. No muscle visible to attach to the shell, Coloring similar to our missing Nudibranch. I do know some snails do have a mottled colorization to their mantles. Appears to be eating off the glass and not the hair algae. OK  I've convinced myself that I must be wrong. That's all the info I can share unless I can get a decent photo. Your incredulous reply will be eagerly awaited! Steve <I'd give this shell a good shaking underwater... just in case this SeaSlug is stuck, can't get out by itself. Bob Fenner>

Nudibranchs floating I have three locally collected Nudibranchs that are black with red rims sort of frilly, healthy seems in every way except that they have all recently decided to climb up the glass and then upside down on the water surface! They are not apparently ill they actually seem to be trying to climb there as they would anywhere else. If pushed a little they sink and grab onto a surface and continue to get around until they reach the glass then back up they go. Any ideas why this may be? << How is your water motion and lighting?  This is just a guess but maybe low oxygen conditions have them moving towards the surface.  Or, maybe low lighting has them moving up towards the lights. >> One started this two days ago now they are all doing it. Have been doing pH adjusting as I let it get way too low (7.5) and also adjusted spec grav as it was too high (1.029). << It would be a good idea to get those things adjusted before adding anything else. >> One has been in there for a month, the other two only a week or so. Have read they don't do too well in captivity any suggestions or new ways to avoid eventual death by starvation? << Where is "locally collected" and have you seen pictures of them in a book?  Fenner/Calfo's Invertebrate book is worth its weight in gold for these types of things.  I also like Sprung's invert book, but I may be able to suggest something else if I knew where you got it from. As for general feeding requirements, I would say healthy live rock with sponge and algae is a good starting point. >> PS this site is very helpful informative and great coverage of topics! << Good Luck. >> <<  Adam Blundell  >>