New 2inch clownfish fighting and white poop

[taherk77]

Hi all I have recently setup a 29 gallon saltwater tank which has been completely cycled. Two weeks before I added a pair of true percular wild caught clownfish in there and they are both 2 inches long. For the first week everything was alright. A clown submitted to the aggressive one by doing the shivering dance and they both started getting along well and would roam about in the tank together. But that was only true for a week. The week later the aggressive one continuously hits the other one and now her fins are nipped. It's not constant chasing around in the tank. I guess it mostly happens at night because i never see the aggressive one nipping. And I guess since the fish is stressed she now has white poop. My tank params are stable ammonia 0 nitrite 0 nitrate 1 ppm. Please help