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craigholman
08/20/2006, 02:06 PM
I have two lettuce nudibranch. A couple of days ago I saw them going over the top of a star polyp. Two days later the star polyp looks dead. I understand there may be some risk with nudibranch. Any thoughts? I don't want to have corals at risk.

Ciarán
08/20/2006, 02:19 PM
Lettuce sea slugs (they are not nudibranchs - they have no "naked gills" as that name implies) dont eat star polyps or any meaty "flesh" at all. In fact, if you don't have one SINGLE form of alga, notably Bryopsis sp. hair algae, your lettuce nudibranch will die of starvation. Adult lettuce slugs are reported to eat certain halimeda spp. but the actual diet of these invertebrates is not actually known, apart from the fact that it is widely accepted that they generally eat bryopsis and bryopsis only. They wont touch your star polyps whatsoever

LeslieH
08/21/2006, 12:44 AM
<a href=showthread.php?s=&postid=7976555#post7976555 target=_blank>Originally posted</a> by Ciarán
In fact, if you don't have one SINGLE form of alga, notably Bryopsis sp. hair algae, your lettuce nudibranch will die of starvation. Adult lettuce slugs are reported to eat certain halimeda spp. but the actual diet of these invertebrates is not actually known, apart from the fact that it is widely accepted that they generally eat bryopsis and bryopsis only. [/B]

Widely accepted doesn't necessarily mean right. If you look at the varous posts on lettuce slug feeding on the Sea Slug Forum you'll see that Bryopsis is mainly eaten by juveniles while adults primarily eat other algae. There are now 3 species known as lettuce slugs : Elysia crispata, E. clarki, and. E. diomedea.

http://www.seaslugforum.net/factsheet.cfm?base=elysclar
http://www.seaslugforum.net/factsheet.cfm?base=elyscris
http://www.seaslugforum.net/factsheet.cfm?base=elysdiom

Ciarán
08/21/2006, 06:36 PM
Thanks for the links

I was referring to Elysia crispata BTW. Whatever it does feed on it is very difficult to give it a proper diet in captivity IMHO. There are a lot of interesting suggestions from studies on the site but none provide a definitive conclusion. There have been suggestions and counter suggestions that they feed on Caulerpa verticillata (as yet unverified). I think the only definite food is Halimeda incrassata for adults (i don't have specific knowledge if this is true). My Bryopsis suggestion was what i understood to be the juvenile food.

All in all, i think it is very hard to keep these beautiful animals alive and well in a captive aquarium with so little knowlege on their diet.