I have seen these come out of other fish and it is an ugly sight. I also want to know what they are and how best to kill them. Right now I am treating 3 red tail baracudas with prazipro and melafix for the wounds left behind. In the feeder tank I once saw a platy trying to eat one. At first I thought it was a bloodworm but then I could tell it was different. The cudas where eating these feeders so you can guess where they got it from. HELP if you can!!!