Our Clarkii Clown is in trouble - can anyone help?

[Pansy-Paws]

We came back from golfing to see Momma, our female clown, exhibiting the following behaviour.
- mouth wide open and stays open
- quicker breathing, but not as rapid as we've seen with some other fish that have been ill
- when we fed the tank, she went up to the food but didn't take any
- her body, directly below the mouth/jaw and down to the fins, seems to be swollen
- swims slowly and now seems to be having some trouble staying 'level'

We're just checking the numbers on our hospital tank before we put her there tonite. Does anyone have any ideas as to what could be happening, and what we might do?

Thanks so much. We've had Momma right from the start of our tank (2yrs) and I can't imagine our tank without her.

Rose