It's all about filtration. The more filtration and water changes you want to do the better you can feed your Oscars. I have a 125 Gallon tank with (2) 8 inch Red Oscars, (1)8 inches Red Tiger Oscar, (1) 8 inch Pike Cichild, (1) 6 inch Black Upside Down Catfish, and (2) 5 inch Pleco. I have (2) Marineland Bio-Wheel Emporer 400 and (2) Rena XP4 Canister Filters w/ 2 and a half of Bio Balls in each canister. I change 20% of the water on Tuesday and 15% on Friday. I feed all of them everyday twice a day. Once in the morning and once at 5pm. They all have shown rapid growth.