I know size matters too...my main goal is to have enough room for all the fish to live comfortably...so I try to get different types of fish meaning free swimmers to burrowers and ones that hang out in the rock so everyone has there own territory and it's not too cramped. Right now I have a maroon clown, swissguard basslet, barnacle blenny, and a recently purchases hi fin red stripped goby. I was wondering if I could get a tailspot blenny or would that be pushing the envelope?