I just bought two new angelfish about 3 hours ago and put them in my 56 gallon tank with my older one. At first they were fine with my older one but then one of new ones started to nip at her fins. I took him out and put him in my empty 20 gallon so she wouldn't stress out. But now that I took out my nipping young one my other one is following my older one around and she doesn't really seem to like it so she'll chase him away. What so I do?