Another way to slow down growth rate is keep the tank temperature lower (around 74-75) rather than using a heater. Your Oscar will eventually grow to the same size anyway, but maximum growth rate occurs at a warmer temperature.
If you're stuck with the 55 gallon until you move out, I'd just get one Oscar not two.
If you're stuck with the 55 gallon until you move out, I'd just get one Oscar not two.
