got 2 baby silver arowanas one is about 6 inches perfectly healthy eating. Other one is about 4.5 inches eating but he tends to go to one corner of the tank and stay abt 2/3 of the way in the water column and randomly darts around always see him staying there was swimming around the top before but I can’t see any physical damage his colors look a little dull but that’s it. Their in a 125 with a green phantom. Have an fx6 on the tank. I don’t think they are fighting either. Any advice?