I currently have a 55 gal. tank with breeding fancy tail guppies, snails, a zebra danio, a pleco, and 3 kribs (1 male 2 female, raised together and do not breed with both females). I have ample room for a few more fish but have no idea what else to put in. The Krib keep the guppy population down to one or two fry a month, so I want to stay away from anything else that will eat them. The pleco can be very aggressive so it rules out bottom dwellers. I do have live water sprite and fake plants for ample "vegetation" in the mid and top level. There is also plenty of coves for the Krib.