go to your lfs and buy the fish ppl brought in(plecos,catfish,cichlids). large fish cheap.
parachromis managuense or jaguar cichlid are egg laying at 4".They get very aggressive when protecting eggs. < very socialable and hardy fish.
jewel cichlids are live bearers. small ... feeder
convicts breed like crazy(not sure of bearing) small ... feeder
If the refugium can be set up as a seperate tank i would use it as a quarentine tank. either for feeder/breeder or sick fish tank
Watch Craigslist and other local classifieds
Put and ad for large and unwanted fish... stay away from piranhas and relatives (pacu,tetras,silver dollars)
cichlids need hiding spots, especially when breeding.
Guppies are a good tank starting fish to get the necessary bacteria needed.
A Native Tank Is Not A Bad Idea Either...
perch,crayfish,turtles,and catfish are very hardy.
as harmless as they seem bluegill and sunfish have been the most bothersome for me.
GL