@Jake1508 Feeder fish can be any species. It does look to be some kind of gudgeon, possibly a juvenile empire gudgeon (Hypseleotris compressa), like @Great Argus said. It can be difficult to identify young fish though. Why do you have feeder fish, do you have a large predator or something? It's better to wean predators onto frozen or pellet foods, it's cheaper in the long run and feeder fish can be lacking in nutrition, they are often raised in filthy tanks and often have diseases that could be passed onto the predator. Also I find it cruel to the feeders.
