Help ID? Too many a problem?

[Willylumplump]

So, I think I found other posts identifying these as sea slugs and harmless, but I started with a dozen or so last week and now they are everywhere, some just floating around. Haven’t put anything in the tank for a couple months. No effects on the coral or fish. I had begun to crush the vermicide snails, but my corals seem to just grow over them anyways. Anyone confirm harmless or experienced a breakout?

 

[KrisReef]

I don't recall seeing these before, but if they are increasing they must be eating something?

Bump!

 

[redacted_]

Some Elysia species, quite lucky! I've tried to keep and breed some in the past but didn't have success. They are not technically sea slugs (nudibranchs) in the taxonomic sense, but are actually sacoglossans which eat algae. Nevertheless, they are slugs that live in the sea

 

[Crabs McJones]

Elysia sp. Correct

 

[elissasoroj]

Some Elysia species, quite lucky! I've tried to keep and breed some in the past but didn't have success. They are not technically sea slugs (nudibranchs) in the taxonomic sense, but are actually sacoglossans which eat algae. Nevertheless, they are slugs that live in the sea

Second all this good info! @OP - If you still have them, I would love to have you send a few to us - I'm a researcher at Harvard. We'll pay to overnight it to the lab and happy to acknowledge you in anything that we use it for :)