My tank seems to have a whole whack of smaller size brittle stars. But they are growing pretty good. Can I do something about this ? Do they munch on corals?
They're generally reef/coral safe. If your tank is big enough, you could get a bongo shrimp. They only feed on small brittle stars so will starve is your tank is small and the stars run out. Look them up, really cool looking shrimp.
They are beneficial to your tank and their population will wax and wane with the amount of nutrients available to them. If you want less, feed the tank less.