In the 30 I had, I put in 2 clowns, 10 blue hermits 3 red hermits, 20 snails, 1 CBS, 1 Cleaner Shrimp, and 12 peppermint shrimp. Never had a problem, and the shrimp ate any extra flak food that sank to the bottom. This may have been too much but like i said, never a problem