I will be getting about 5 Angelfish as soon as my 55 gallon tank finishes cycling. However, I am concerned about the over all health of the tank. Should I look into getting some sort of bottom feeder or algae eater for the tank? I want something that will remain relatively small and would make a good companion for Angelfish, preferably something that will do his own thing and won't bother the angels at all if possible. I just want to make sure that my tank is "balanced."