Up untill recently I had 2 oscars and found they needed regular water changes (which you provide) I fed them on prawns,chicken,ox heart,discus granules,steak and the only time they lost interest and got sick was when the PH dropped.I did 50% water changes weekly and within that 7 days the ph would drop from 7.2 to to 3.4. They were housed in a 950L tank with 8 Bala sharks.