I have no idea what these yellow sea slugs are, but they're everywhere. (Video)

[Perpetual Novice]

I have tried to get good photos for months since I saw the first one. I only see them when I disturb the aquascape but at night they come out in force. They're about a centimeter or less and bright solid yellow. Today I got a lens kit for my phone. I couldn't take a picture because I couldn't focus it with the flash but I was able to take this video instead.

They don't seem to be hurting anything. They've been around for months now and I have many colonies of zoas that are totally happy and no hard corals. They don't seem to cluster around corals at all in particular. Could they be eating algae?

 

[Perpetual Novice]

Does anyone know what they are? Should I be concerned?

 

[ScottR]

Elysia sp. ok. Eats macro algae

 

[Perpetual Novice]

Elysia sp. ok. Eats macro algae

whew. Thank god. They're very numerous. Maybe hundreds.

 

[ScottR]

whew. Thank god. They're very numerous. Maybe hundreds.

Wow. That sounds out of control. Although these aren’t bad, there’s not a lot of people that would want them.

 

[Perpetual Novice]

Wow. That sounds out of control. Although these aren’t bad, there’s not a lot of people that would want them.

I guess step one would be to get my algae under control. Or I could just think of it like Ill never need to buy snails from my LFS again. ahah

Do you know if they eat bubble algae? red or green? I've got some of that in a nano setup but don't want to risk a rogue emerald crab around the corals in there.

 

[Perpetual Novice]

also, I think I've identified the species Elysia Obtusa

 

[ScottR]

I guess step one would be to get my algae under control. Or I could just think of it like Ill never need to buy snails from my LFS again. ahah

Do you know if they eat bubble algae? red or green? I've got some of that in a nano setup but don't want to risk a rogue emerald crab around the corals in there.

They’re commonly called caulerpa eating sea slugs because they prefer caulerpa I guess. But they’ll eat some other types of macro. Pretty sure they won’t touch bubble.

 

[ScottR]

For bubble, perhaps look into using vibrant. It’s a heterotrophic bacteria that actually eats the algae.