I put 4 peppermint shrimp in one tank that had aptasia everywhere and they knocked out the problem completely. I also have another tank that has like three or four peppermint shrimp in it that has three aptasias and they wont touch them. So peppermint shrimp do work but it depends on the individual peppermint shrimp and how much other food they have to eat atleast in my expierences.