Anybody got and idea what these things are?

[Anonymous]

If I had to make a specific guess I would think they were in the family of Sphaeromatidae, in which case they should be harmless. But I am not reliable at identifications, so don't rely on anything I say.

Yup. Harmless detritivores. I think the males have the little 'fins' on the back. I've had these aplenty in my fuge. They seem to wax and wane like any other pod. They look a little bit like Cirolanid isopods (the bad ones) too.