I have a 29 gallon tank that I was thinking of doing a single species tank with or even just a single fish. The dimensions are 30L x 12W x 18H. I don't have it set up yet so I can't give you temp or parameters but I'm going to cycle it and make sure the parameters are right when I decide on the fish. I was thinking of a bloody parrot or an angel fish. Would either of these work? I know bloody parrots are kind of controversial, so if anyone has any reasons against them, I would be happy to hear it. I just really like how they look and their personality. What other kinds of relatively large (3-4 inch) fish could I have one or two of in this tank? I would prefer some kind of fish that is interactive and playful. I like cichlids but I don't think my tank is big enough for most kinds.