Is it possible to have too many cleanup crittters? I have a 30gal long tank with 2-3" Argonite (I know I need more) 20lb figi live rock. 4 damsels, anenome, feather duster, arrowcrab, 6+" worm sof some sort. 6 snails and a camel back shrimp. I was thinking of adding more crabs and snails...