Alright, I have no idea what this is...it may be nothing. But on a few of my corals I see these rectangular green pieces. I have posted a few pictures below, let me know what you think. There is a hole rock that is covered with the stuff that I bought from a fellow reefer.
I cannot see them moving a noticeable amount, but I know they are moving somehow because they are appearing on other rocks now. Flatworms are harmless right?
Take a baster and blow at them, if they fall off easily they are probably flatworms. You can suck them out with some airline tubing or use flatworm exit, they aren't bad really just ugly and will accumulate wherever there is low flow.
