Try Apistogramma Cacatouides. They are hardy, relatively easy to breed, have great color, and are somewhat peaceful towards other fish. They like a temp around 79 with a ph of about 6.8 however i keep mine in 8.3 and they do well. Need atleast a 10 gallon tank, a larger tank may be needed depending on his temperment. They should have tetras, and other fish to make them feel safe aswell as some caves to hide and spawn in. They eat about everything ranging from frozen bloodworms, frozen brineshrimp to dry pellets and flakes. The seem to love lots of bloodworms, which seems to get them in the mood to spawn. Should have a fairly planted and stable tank. They also come in a few color morphs, such as Orange flash, and Triple red. Personally i like the orange flash better because usually they are cheaper and the males have a nice orange tail and blueish fins. Great fish to have for a community tank.
PS. I wouldn't recommend pacus, they will get huge!
Good luck,
Daniel