Tried adding new fish to my 420 gallon tank,every fish I add he shreds just added nine inch Red devil now he is messed up,he ate my nine inch Jaguar Cichlid.Gator gar is about 28 inched long and very thick,he is in a 420 gallon tank that is seven and half feet long 24 wide 30 tall I have a 20 inch red tail Guarami 16 Inch flag tail 24 inch arow and a 13inch Oscar which the gar nips at so he is getting hole in the head from the stress and a Spiney Gulf soft shell Turtle. Does any one have any Ideas of other fish that can hold there own with Gar? I do not feed live, and feed gar heavy to try to keep aggression down.