Lion, I really am sorry to keep bugging you like I am, but, if I WERE to keep my 55 up and just take really slow, rather than downgrading, what fish from that list could I keep? I don't want the sleeper goby anymore..because I heard you have to replace the sand bed every couple years to keep them healthy. I know the tang and the butterfly won't work in this size tank, but what about everything else? What all from that list could I keep in a 55? Also, is it true, that at night, firefish lock themselves into a bolthole and won't move for anything..even if a hermit crab gets to it, and tries to eat it alive? I have dwarf blue leg hermits, but I want to get some purple firefish..is this going to be a problem?