Howie, I had a cleaner shrimp in with the ponys awhile back. I made sure I fed it first then it left the ponys alone. However, the shrimp do not help with algae on the ponys, the algae occurs from the low water circulation and flow in the tank. You can get it off by blowing it off with the pipit or turkey baster or you can gently rub the pony with your finger.