I have a Vampire fish/hydrolycus armatus or whatever you want to call it, but thats not important right now. He has some black almost small snail looking thing attached to his lip. Its possible feeder goldfish could have introduced something. I also accidently let the water get pretty cold, much much colder than usual. I have already put the heater on. I going out, but im going to come back and post a picture of it.