Hey guys. I have a question. A couple days ago, I brought home a baby angelfish and (of course, after acclimating) put him in with my current adult angelfish, Kai. I named the baby one Cole. Kai, was, as expected, chasing Cole, but not to hurt. More like a "This is my territory," kind of chase. She wasn't doing it that much today, but, nonetheless, I decided to try something. I netted Kai and put her in a bucket filled with tank water, and covered the top with a towel. I rearranged all of the tank decorations (I didn't alter anything about the water) and then put her and the water in the bucket back in. Kai is now exploring the tank, but now whenever Cole comes over by her, she starts rapidly opening and closing her mouth, sometimes backing away from the little angelfish. Cole is now completely unafraid of her, and even swims next to her, without her chasing him. My question is about the opening/closing of the Kai's mouth when Cole swims by. Has anyone experienced that in angelfish? Is that submission? A sign of dominance? Or do I just have a very strange angelfish? Another thing I did today was take Kai, the large adult, out of the tank and put her in a bucket of tank water. I covered this bucket with a small towel. I rearranged all of the plants and switched out some decorations. When I was done, I released Kai back into the tank. (I hadn't done anything to alter the water itself, so no need for acclimation.) Kai suddenly became submissive to the tiny angelfish. He swam up to her to greet her back (being the happy little guy he is) and she folded her fins back and opened and closed her mouth rapidly, backing away from him. He seemed surprised by this at first, but now follows Kai around the tank, just watching her. If she stops, he sometimes either dances around her or just looks at her face. It's funny how drastically their relationship changed with just the simple act of taking Kai out and rearranging the decor. Here the two are. Kai is the big black one, Cole is the little koi.