Nudibranch ID

[ZzyzxRiver]

It’s tiny, orange with a dark interior, and kinda cute. But I have no idea where it came from—nothings been added to the tank in well over a month. Nudis are typically the color of what they are pests of, right? But my orange blasto and orange Discosoma are both in perfectly fine health.

 

[ZzyzxRiver]

I should have googled around first- I found this thread and it’s almost certainly what I have. I have a sixline wrasse so it probably doesn’t have a long life ahead of it even if it has survived two months already.

 

[ISpeakForTheSeas]

A couple of Elysia species look remarkably similar to a few Vayssierea species:

For distinguishing them and info on them:

If they're tube-shaped/lacking leafy "wings" on their backs, then they're V. felis; if they have the leafy "wings," then they're an Elysia sp.

Vayssierea felis or another species in the genus (some of which are only distinguishable from V. felis by their radula - basically their teeth) is a good guess (these are the nudibranchs that are thought to eat Spirorbid worms).

Yeah, that's an Elysia sp. Sacoglossan Slug (A.K.A. a Lettuce "Nudibranch"), and it's an herbivore - if it's from the Atlantic, it's E. flava; if it's from the Pacific, it's E. obtusa

Elysia flava or E. obtusa - harmless/beneficial Sacoglossan slugs. 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

 

[ZzyzxRiver]

A couple of Elysia species look remarkably similar to a few Vayssierea species:

For distinguishing them and info on them:

As always you deliver! Can’t wait to read up on these.

 

[ZzyzxRiver]

While basting rock tonight I saw at least ten more of these guys on the rock and substrate and glass… so we’re about to find out real quick whether or not they’re harmless, LOL.

 

[ZzyzxRiver]

My aquascape is now crawling with dozens and dozens of these guys. There cannot possibly be a spirorbid worm left--I haven't seen any. And yet there are more and some seem to be getting bigger. None of my inhabitants seem bothered, though! I'm so curious how long this will last.