hard to tell.. looks like something between a worm, rubber band, or bugger. i have seen flat worms in chaeto (bad) and worse, medusa worms (which that could be) - but cant tell from the pic - but the color is correct
I did a FW bath with an air stone, and manually removed all of whatever they were. I don’t know if that’s bad for the chaeto, but now I have it in SW with the air stone. I’m still concerned about eggs or anything too small to see. I’ll try to get some better pics, but at this point I just don’t know if it’s worth the risk.
well without better information, i am going with buggers.
j/k
i had medusa worms in a batch.. pulled them out .. put the chaeto back and never saw another. I also run UV which may help.. and too be honest, anything that made it into my tank would probably be eaten