Or a single small cichlid(preferably 6" and under) Firemouth, Convict, Port Acara, etc. You could keep a couple of dithers with your cichlid such as some Giant Danios. Spotted Climbing Perch would also be a badass occupant they are true predators I could also see a pair of greenspotted/figure 8 puffers if your willing to go brackish they grow slowly so this could be a nice home for them for some time.
2 GTs get way to large for a 15G tank, in theory 2 Jewels size wise wouldnt be to bad but having 2 cichlids of anytype in that small of a space is asking for trouble IMO. Id get a pack of 5 Exodons...and yes they would maul down a feeder
wat about Mouth Almighty? they get to ruffly 6-7". they are like a miny barra. they are agressive feeders and are called mouth almighty for a reason.Glossamia apiron is there scientific name.