So I have a 3 gallon, filtered, and newly planted tank with gravel. The problem is not that I have algae on the walls of the tank, which is easy to clean with a sponge, but that the rocks have turned a brownish, ugly color. I want something to eat the algae on the rocks. Would a group of cherry shrimp do the trick? I could go with a nerite snail but that means a lot of poop instead apparently. I suppose an amano might do that too, but I've never had shrimp, so I don't know what kind of algae they eat, and if they clean rocks.