If you are talking about the 15 gal community i think you should be able to fit a little bit more. I like seperating a tank into 3 catigories (stratas). The top, middle, and bottom of the tank. You have a few bottom feeders already but i think you could fit a couple more kuhlies. Keep alot of hiding places in the tank because you have alot of fish that are nocturnal/hiding fish. I would say you might also be able to fit a couple of more guppies or some more small fish. IMO i would stay away from tetras because they need 5+ fish to be really happy and i think that would be overstocking the middle section (strata).
