Nudibranch or sea slug?

[Nicolemcd777]

Good morning everyone,
We woke up this morning to this. Is it a Nudibranch or a sea slug? And is it good or bed? I’ve looked it up but I can’t fine anything that looks like it. Please let me know if I should put it back in my tank or get rid of it.

 

[Kasrift]

Good morning everyone,
We woke up this morning to this. Is it a Nudibranch or a sea slug? And is it good or bed? I’ve looked it up but I can’t fine anything that looks like it. Please let me know if I should put it back in my tank or get rid of it.

Looks like a sea lettuce slug Elysia crispata. @ISpeakForTheSeas is a good IDer of these things.

 

[Nicolemcd777]

Is it good or bad tho? I’ve looked but I don’t see anything with its colors it’s a orange/yellow color the picture doesn’t do it justice

 

[Hats_]

Algae eater, generally dont live that long in reef tanks. Wont harm anythijg unless you keep macroalgae

 

[Nicolemcd777]

Algae eater, generally dont live that long in reef tanks. Wont harm anythijg unless you keep macroalgae

So it won’t hurt any of my corals right?

 

[Kasrift]

So it won’t hurt any of my corals right?

Correct. It is a good guy. Make sure your pumps and wavemakers can't suck it up.

 

[ISpeakForTheSeas]

Yeah, definitely an Elysia sp. sacoglossan slug, looks like probably E. obtusa or E. flava (they're similar enough that molecular phylogenetic analysis was needed to determine that they are in fact different species).

Either way, as mentioned, they're harmless algae eaters:

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.