I own 2 featherfin catfish, one is 3.5 inches long and the other is 2.5 inches. I also own a 4-inch pictus catfish which was in the tank first and had established his own territory long before the feathers were introduced. They are in a 30-gallon grow out tank with some sparse vegetation and plenty of rock caves in which to hide. The bigger of the 2 feathers has decided to hang out in the same cave as the pictus and never caused a problem until recently, he has begun biting the pictus's tail and they go in circles fighting quite aggressively. I do not know how to stop the feather from instigating or how to get the pictus to move out and claim a new cave. Any suggestions?