My male dovii which is approximately 8.5 inches has really become aggressive as of late, used to stay away from python water change tube, now tries to attack it, all day long he is biting the FX6 and FX4 outflow tube, this attitude has came out of no where. I imagine this behavior will only get worse, he is solo in his 210 gallon tank. I have him eating hikari cichlid bio-gold, massivore and tetra jumbo krill.