Wolf3101;1112454; said:actully this will depend on what 50 gallon tank you have...a standard 50 is basicly a 55 short...(48" long) However a 50 gallon tank in a breeder configuration....only 3' long but a lot wider....would be fine for an Oscar for a very long time. You have to concider shape as well as gallons when figuring a minimum and, of course, always go as big as possible.
50 gallons may well be the upper limit NOW but that may change long before the Oscar needs more room.