OSCAR?
its dependes on what you like preditor, comunnity, species tank, native,cichlds, breeding?
ill give u an idea for each 1!!!
preditor1scar
preditor2:birchir with an african leaf fish
comunnity1:tetras/danios
comunnity2:barbs/silver dollars
species1:maybe a big school of tiger/green barbs
species2:exodens
native1: pumkinseeds
native2: creek chub/ variousminnows
cichlids1:flowerhorn
cichlids2: green terror/jack demsey
breeding1:convicts 1-2 pairs
breeding2: livebearers
breeding3:rams
breeding4:
if u like cichlids i would go with an oscar.......cichlids very agressive will eat feeders(i have an oscar in a 55g)(he ate 7feeders yesterday)hes llike 5-6inches