Without seeing pics of "the diamond goby" I'd assume it's a diamond sleeper goby. Please, for Christ's sake (and the fish's) take it somewhere else. Even your 55 isn't established enough to keep it fed. Who the hell is selling you all this stuff for a month old 24 gallon tank?
I'm not trying to be a "meanie pants" and was even a *bit* perturbed at how harsh a few people were being to you. But this is just too much.
"Awhile" is not 9 days, that's a minute when talking about a reef tank. My sleeper got stuck under a rock (we thought he was dead) only to appear a week or so later VERY malnurished, and in dire straights. We've been feeding him like mad to get him back to where he can even feed himself (One of the lucky few to get one that'll eat prepared foods) and I don't want to see you go through it... That's of course if you even care about the animals, which I find hard to believe because you keep flooding this poor 24 gallon tank.
/rant