Green wavy snail without shell??

[ssatter]

Just down feeding a new open brain coral tonight and spotted this at first I thought it was left over nori but then I saw it's snail like head tentacles? What is it?

 

[vetteguy53081]

Just down feeding a new open brain coral tonight and spotted this at first I thought it was left over nori but then I saw it's snail like head tentacles? What is it?

I cant expand pic but may be a lettuce sea slug

 

[Aquadude1]

It looks like a nudibranch of some kind maybe a lettuce nudibranch

 

[ISpeakForTheSeas]

Elysia flava or Elysia obtusa - Sacoglossan Slugs; algae eaters. To add to the quotes below, it seems at least some adults of some species can survive feeding on algae that isn't their preferred food, but juveniles cannot:

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. As mentioned below, I don't know if these are required feeds or just strongly preferred feeds:

Some lettuce slugs (typically from the genus Elysia) will eat nuisance algae species, but their wild diet varies pretty drastically from one species to another, and some species have some pretty specific wild diets (I don’t know if these are required diets or preferred diets, but Reef Cleaners reports that they'll eat just about any green, fleshy algae). That said, Elysia slugs generally feed on siphonalean algae such as Caulerpa, Codium, Acetabularia, Halimeda, Udotea, Byropsis, and Valonia spp. So, in theory, these guys should eat nuisance algae that pops up in your tank.

 

[ssatter]

Here's another shot in the center. Really cool. Thank you everyone!