Corynactis

[SanClementeEric]

Recently bought a rock with nems on it and while moving it around, I noticed two of these on the bottom of it. Sorry for the crappy pick but the time wasn't right to have brighter lights on. After research today I'm pretty convinced they're Corynactis of some kind. Anyone have any experience with these in their tank?

 

[bues0022]

They are called ball anemones. Harmless. They prefer the dark, backside of rocks. They are filter feeders and will increase in numbers as nutrients provide, but will not become problematic in the least. I've had them in several tanks. I always liked having them - adds a little character to an otherwise empty area.