Should I assume every tan or grey Isopod is a bad guy?


New member
I've seen a fair number of isopods with body shapes like Cirolanids in the tank at night, mostly eating algae or bits of food. Should I assume that all of them are Cirolanid type bad-guys that should be killed on sight?

I've seen at least a half dozen or so of them in varying sizes, so I assume that I likely have a breeding population. What's the best way to eradicate them if that is what they are? I'll eventually want to have fish in the tank, and I'd rather they not get eaten alive.

Sugar Magnolia

Mother of Dachshunds
Staff member
RC Mod
It's possible they are sphaeromatid isopods, which are harmless. The only way to know for sure is to capture some of them and take some pics. Also, sphaeromatid isopods can curl into a ball like pill bugs, while cirolanids can not.