Today I discovered that both my PBass have darkened in color and are acting very different from yesterday. The black markings on the side of both of them has changed from a stripe to a spot and the golden markings have become more than twice as prevalent. The dorsal fin on both of them has become black and is now nearly always erect when it would be up only on rare occasions. Both have changed there disposition as well from being fairly meek and hiding most of the time to becoming very bold. I have noticed that one of them (I believe the male of the two) is puffing out his gills and is picking on the other PBass (I believe is a female). He is charging and coming close to nipping the side of the female but always stops as she swims away. These two fish have been raised together since they were hatched and I have never seen this sort of behavior between them. They are each about 6 inches long and are being fed minnows. Any thought on what has triggered this behavior?