Yep clowns behave oddly, however the rapid breathing is not normal and a sign of some issue. I agree that your tank seems to be cycled so ammonia shouldn’t be the issue IMO.Yeah they are odd. The other night I noticed they were sleeping sideways near the surface. Apparently that’s normal. Also the one was having seizures and read that was normal. WEIRD. They never fail to interest me.
There is a good chance it is disease or parasite related, so the most help I can be is to the tag the forums resident fish disease expert @Jay Hemdal to see what he thinks.