Nudibranch?

[D12monkey]

Found this on a frag I just received. Any Id would be grateful. "reef safe" or not?

 

[Maritimer]

Looks like possibly an Elysia slug, which is a vegetarian. Not sure if they're helpful with algae, or just eat caulerpa or similar.

~B.

 

[D12monkey]

Looks like possibly an Elysia slug, which is a vegetarian. Not sure if they're helpful with algae, or just eat caulerpa or similar.

~B.

Thank, this slug is only about 3-4mm fully stretched out. Debating adding it to the tank. It was on a Zoa frag I got.

 

[Maritimer]

I probably would ... but I have angels and parrotfish in my reef.

~B.

 

[ISpeakForTheSeas]

Definitely reef-safe. That's either Elyisa flava or Elysia obtusa:

if it's from the Atlantic, it's E. flava; if it's from the Pacific, it's E. obtusa

They're herbivores, with E. obtusa known to feed on Bryopsis, while E. Flava is thought to feed on Cladophora.

it seems at least some adults of some species can survive feeding on algae that isn't their preferred food, but juveniles cannot

If you don't have access to their preferred feeds, you can try some of the below or another green algae, but no guarantees they'll feed on it/derive adequate nutrition from it:

Elysia slugs generally feed on siphonalean algae such as Caulerpa, Codium, Acetabularia, Halimeda, Udotea, Byropsis, and Valonia spp.