Ok so it's been about three days now she has been doing this. 20 gallon tall tank 2 Darwin black percula clowns a pair. My female has been lying on the floor and breathing heavy. Male stays right by her side. At night when lights are off the stay about 3/4 of the way up the tank in the back corner. I got them on Sunday they were fine in there tank and bag but as of Tuesday she started this she still swims fine still goes for her pellets but keeps laying on sand and breathing heavy. Had water tested nitrate and ammonia 0 phosphate was on first level that's about all tanks at 80 degrees