Then I'd say get your mini-cycle under control before you even consider adding any more fish to that tank. Have you checked AqAdvisor to see what your stocking and filtration levels are at right now? If not, I would do that before adding anything else. That'll also help you determine what might be a good fit for your tank. You might get another dwarf fire gourami, but the opposite sex of the one you already have. I can't think of any centerpiece fish that are a good match with gouramis in a tank that size other than another gourami, to be honest.