when i bought a fish months ago the guy gave me some of his sand with the fish.it started off with a few now i have hundreds of these things in my tank.i don't have a picture but everyone says they are cleaning the bottom of the tank and is good for the tank.well they are everywhere and now are clinging to the glass.what could i buy that would maybe control these things.i have a 75 gallon community tank.sea apple.pencil sea irchin,two clowns,two six line wrasse,purple fire fish,neon black velvet damsel and a blue devil damsel