IMO you are close to being over stocked, but you could squeeze a few other creatures in the tank. "Other" creatures meaning 5-6 ghost shrimp, an dwarf african frog, or a snail. I don't recommend adding any more actual "fish." And if you didn't know it, those guppies are going to breed like crazy. If you didnt have the guppies, I'd say you could add a male betta if you wanted.