I have four discus in a 65 gallon tank along with a ret. stingray, clown loach, and black ghost knife. The fish all get along with eachother from species to species, but my discus fight all the time. I feed them 2-3 times a day, once or twice with live black worms, hikari discus pellets, or freeze dried tubifex worms. I cannot get them to eat the frozen brine or bloodworms. Three of the discus are 3-4" and one is around 5" so they are quite young. Naturally the 5" is the boss. Is there anything I can do to get them to stop fighting? They chase the newest one in the corner all the time and bite at it whenever it tries to eat. Please help!