Well, like I said before, not going to hurt to try.. Just get some worms, and put them in a container of some sort full of damp shredded newspaper.. (no ink on it..) and leave them for about a week.. That will clean them out inside..
A lot of people say The fish's stomach is as big as one of it eyes.. I'm guessing that does not apply to fish like these..
http://www.aquaticcommunity.com/gobyfish/dragon.php
That has a little info about feeding, and some other things about dragon goby's you might be interested in.