there are these little white things in my fish tanks. they are about the diameter of a dime or nickle long and are thinner than a piece of paper. they group together at the dry part of the glass above the water and look like wet dog hairs. sometimes they turn a pinkish red when they really group together. i try to knock them into the water to kill them because they seem to hate it. they also group on my airline tubing at the top where its dry and they have turned a pink-dark red. how can i get rid of them? please help. i don't want to do a water change unless there safe to me.