Possible Locked Jaw?

I have this on the malawi forum, but also hoping for some insight here, since this can be a non malawi related issue.
-----
Greetings All,

I have a dominant male peacock with a possible lock jaw, and wanted to look at your input.

His mouth is not completely closed, but acts as if he was holding. With food, he chases it but does not take in any food and his mouth remains semi-open (again similar to females holding eggs and hungry). I have also witnessed him trying to move sand, but he can't open his mouth to take it in.

He is 100% male, showing colors and finnage, and not hormoned. He has spawned before with my females. I have another sub-dominant male in the tank with 8 other females. I haven't witnessed any fights because this dominant male owns the tank. He seems much more submissive now though since he isn't opening his mouth.

Water parameters are normal.

If this is indeed a locked jaw, should I attempt to open it similar to methods for stripping fry? It would be a gentle process, but I'm afraid of permanent damage.

Please let me know what you think. Thanks!