I realize you came here for help. So I will attempt to give you some advice, weather or not you choose to listen is entirely up to you.
The tank is too small for one let alone two Oscars. It is very diffacult almost impossibile to keep the water perameters within acceptable levels in such a confined space. This is not a good situation and is extreamly detramental to the long term survival of these fish. If you can't provide a much larger tank, please for the wellbeing of the fish rehome them.