As per James above.. the 75 gallon is barely enough to house an adult Oscar on it's own. I might suggest adding more filtration, if that's the tank you are going to stick with, and it shouldn't have more fish.Cwag said:I currently have a 75 gallon tank with, a Oscar, jack Dempsey, pleco and a jewel all currently smaller then 5". I'm wondering if there is anything else I can add to the tank?