Another ID plz

[knight2255]

I don't have a photo unfortunately.

I just turned on the lights to my DT to see a little jellyfish floating around with 2 long(4-5") threadlike tentacles that it would shoot out and retract quickly back in. I found 2 other spots on the rockwork where the same type tentacles were shooting out and retracting.

What is this and is it bad?

 

[Hormigaquatica]

Sounds like a type of ctenophore aka comb jelly. They're fairly short lived and pretty harmless, though the tentacles can irritate more sensitive corals sometimes. They seem to hitchhike their way in on toadstool leathers more than anything else in my experience.

 

[knight2255]

Thanks, that does indeed seem to be what they are, ctenophore tentacula