Mystery slug in aquarium

November 29, 2001
From: Regina Barrera

Hello, I noticed in my tank some yellow "slugs" (I think) on the glass. Now there seems more of them then before. They look like yellow logs with two large atennae. I'd like to know what they are and if they are reef safe? Sorry for the quality of the photo
Thanks Ahead!


Barrera, R., 2001 (Nov 29) Mystery slug in aquarium. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Regina,
It seems to be a species of Elysia. If you want to see some variety, have a look at the Species List for photos and information on a numnber of different species of Elysia. They are herbivores which have probably hitched a ride on some green algae or an algal covered rock. They may not survive in your aquaria but I can't imagine them doing any harm.
Bill Rudman

Rudman, W.B., 2001 (Nov 29). Comment on Mystery slug in aquarium by Regina Barrera. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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