I have found mixed reviews on this so I thought I would check here. I have these very tiny feather duster looking creatures all over my DT and sump. There are a few dense groups, but otherwise they are spread out. Everything seems to be doing well and parameters are in check. From what I can find these are not an indication of anything bad, and have read that it is a good sign. There is a dense pocket at the base of my own torch. they are also growing on the shells of some snails and crabs. 1 empty shell has they growing out of the shell.
Should I be concerned?