In the past week I have started a new snowflake clown pair in a fluval evo 13.5G. I had bought the clown as a pair online, but one of the clowns every so often chases and goes after the slightly smaller clown. At first i thought it was just for dominance to be the female, but the smaller clownfish now has a small amount of fin rot on one of his front bottom fins. What should I do and what is the cause? Should I put up a divider temporarily?