Large brown frilly slug thing?

[CmMagenta]

I found two in my frag tank. No idea what it is. Maybe a nudibranch? I'm waiting to see what it eats but so far it's just moving around on everything

 

[CmMagenta]

 

[CmMagenta]

Found a 3rd one

 

[ISpeakForTheSeas]

I'm pretty confident that's a Marionia sp. nudibranch, but I'm not sure which species. Either way, their diets should be pretty similar:

If it is a Marionia sp., then it likely eats soft corals/gorgonians. If it's a similar looking species from a different genus, then it most likely eats either soft corals/gorgonians, or hydroids. (Looking at your latest pic though, I have to ask - are those hydroids in the macroalgae? If so, it may well be feeding on those.)

Either way, they're still nudibranchs, so they'll likely only feed on a handful of species (most that I've found are only thought to eat species from ~1-3 genera), so it'll most likely starve in the tank.

 

[taricha]

It looks like it would blend in well on that gorgonian in the background of the 1st pic.

 

[CmMagenta]

Thank you. I think they are breeding in that tank so I need to figure out what they are eating. They started coming out after I turned the lights up brighter

 

[CmMagenta]

I see more in there (most are smaller ones)

 

[CmMagenta]

On an exciting note, I also found many baby serpent stars hiding in the same system. Looks like my really big ones are parents now. They are ranging in size from 1 inch to 3 inches so it's possibly several parents. Here are some of the adults. They are really big

 

[Kerbash]

On an exciting note, I also found many baby serpent stars hiding in the same system. Looks like my really big ones are parents now. They are ranging in size from 1 inch to 3 inches so it's possibly several parents. Here are some of the adults. They are really big

Wow! I didnt realized these can reproduce in your tank!

 

[EeyoreIsMySpiritAnimal]

I see more in there (most are smaller ones)

That's crazy! If you come to Houston anytime soon, I'll buy a few from you

 

[CmMagenta]

It swims! And I found more. I think it's eating aptaisa. I have one in a qt tank with possible food items to test my theory. Maybe it's the giant rainbow nudibranch?

 

[ISpeakForTheSeas]

Maybe it's the giant rainbow nudibranch?

It's definitely not Dendronotus iris - and not just because that's a coldwater species from the US West Coast (which reportedly feeds on a Tube Anemone/Ceriantharian, not a true Anemone/Actinarian).

Again I'm confident this is a Marionia species, and I'd assume it's eating the soft corals/gorgonians in your tank (with a low probability that it may be feeding hydroids).

 

[CmMagenta]

It's definitely not Dendronotus iris - and not just because that's a coldwater species from the US West Coast (which reportedly feeds on a Tube Anemone/Ceriantharian, not a true Anemone/Actinarian).

Again I'm confident this is a Marionia species, and I'd assume it's eating the soft corals/gorgonians in your tank (with a low probability that it may be feeding hydroids).

Damm. I was really hoping it would be beneficial. I put in several frags of different corals in the qt tank with it. I've seen it crawl on the gsp and algae but not sure it's eating any. Although that would explain why my gsp doesn't spread. I'll keep watching to confirm its a coral eater.

 

[CmMagenta]

It's definitely not Dendronotus iris - and not just because that's a coldwater species from the US West Coast (which reportedly feeds on a Tube Anemone/Ceriantharian, not a true Anemone/Actinarian).

Again I'm confident this is a Marionia species, and I'd assume it's eating the soft corals/gorgonians in your tank (with a low probability that it may be feeding hydroids).

Some gorgonians are in there too