They will probably fight even worse being the same size. The way that particular species works, the female is the largest, and sometimes she will force the male (the smaller one) to show submission. That is probably what you were seeing at first, the establishing of dominance by the female. Now, unfortunately, since they are the same size, they will fight to find out who is dominant, and the winner will become the female (if not already female). I would be very careful introducing them again, it's possible that they could fight to the death since they are close to the same size.
Or, they might not fight at all. But not likely. The only question is how bad is the fighting going to be. You need to make sure that you will be home for the day when you put the clown back in the tank. Know where your net is and be ready to act. Keep a very close eye on them.
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