What the hell is wrong with nemo!!!

[jason604]

This morning when I checked on my tank my male nemo seem to have his mouth wide open and didnt close it once. I thought he was just being will but even till now its still not closed. That can't be normal been over 12 hrs. I fed them to see if he will close it to eat but he seems like he wants to eat n chase the food then does nth. I looked into his mouth n his throat looks like its swollen and not that big but mouth is fully open like locked jaw. How I fix him?