The tank used for raising baby angels gets much dirtier than a normal aquarium. The reason: baby angels eat fresh brine shrimp. I grow the shrimp in a separate tank but because they are so small, any that are not eaten often settle into areas that can be difficult to reach, especially if there is gravel in the tank.
What I've done instead is add snails to the tank. They don't swim so I don't have to worry about the snails going after the babies. Instead, they stick to the bottom gravel or they clean the glass and other surfaces.
They are also easy to remove. I can simply stick my hand into the tank and grab one. I don't have to use a net, which could easily snare some babies.
I have also placed snails in a breeder tank until the pair begins to lay their eggs. However, in this case, I do use a net, as the breeding pair can aggressively go after any hand in the water as they seek to protect their newly laid eggs.