Im guessing they are bored bro. They are piscovores by nature ,if there food is too easy they get bored with the easy meal and need something to occupy there time .Put a couple of floating fake plants in the tank and put a strong power head on one end , set it up on a timer so it will come on every once in a while and move the plants around just the smallest burst of time .You will catch them playing (football) with them and you better hook us up with some videos of that . It helped my fish out and they were marked up considerably less . Works pretty well with most of the bigger cichlids,oscars are like dogs if you give them toys.