i posted here a few days ago saying my oscar was sulking well it has been a week and i bought him a friend and they got along great but they still both kind of didnt act right they ate only when the food sunk to the bottom they were not getting bullied cuz they were the only two fish in my 75 gallon tank. So last night i go in and one of them is dead and this morning the other one died i check my water two days ago and it was fine this morning i checked it and the nitrates were way too high what caused this and were my nitrates high the whole time maybe this is why the oscars never really acted right does anyone know??? cuz i want to have fish in this tank but