Hi,
I wrote about mouth hyperextension in my Advanced Marine Aquarium Techniques book - I've never seen it in jawfish, but it sure sounds the same, here is an excerpt:
Hyperextension of mouth: In an unusual medical case, a blue line angelfish, Chaetodontoplus septrionalis bit so vigorously at some algae that its mouth became stuck in a hyperextended position. While the fish could still breath, it could not feed normally. As one tenet of medicine is, “First, do no harm” the fish was left to its own devices to se if it would recover on its own. After a day with no improvement, the fish was anesthetized using MS-222, and the mouth was gently manipulated. The mouth seemed completely locked in the wide open position. Eventually, a small bone was located at the top of the isthmus between the jaws and the fish’s head. Depressing this, (like the locking spine on a triggerfish) allowed the entire mouth structure to return to its normal position. The fish began feeding normally the next day.
Since jawfish are so difficult to handle, I think I would just "wait and see".
Jay Hemdal
