This is not good. CFC has kept needlefish, and may know more about first aid. The bad news is that damaged jaws on needlefish, and their relatives the halfbeaks, can be fatal, by allowing in opportunistic bacterial infections. The good news is that, with my halfbeaks at least, if you keep the damaged fish healthy, they heal quite quickly.
Now, needlefish are significantly more delicate than halfbeaks, but I'll give some advice anyway. If you put some sort of antibacterial medication (like Melafix) in the aquarium, that should help with any infections. Adding salt is another option, though while needlefish are tolerant of salty water, a lot of other fishes aren't, so it will depend on their tankmates. You definitely will want to step up the water changes. I'd be doing 10-20% daily for the first week, to keep the bacteria count down.
As a last resort, dabbing iodine might be useful if there is a definite wound. This means taking the fish out and wrapping it in a wet towel, and then using a q-tip to dab the iodine carefully onto the wound, avoiding sensitive areas like the gills or eyes. This is quite commonly done with koi carp. Iodine is non-toxic, though the fish probably feel the sting just as badly as we do when using iodine! Iodine sterilises the area, speeding up the healing process.
Cheers,
Neale
i watched my needle fish break its lower jaw this morning.somehow a hair got in the tank and got caught in his mouth and it totally freaked out hitting the glass full speed
it is snapped downwards right at the tip.
there is also a ball like swelling at the very tip of the lower jaw now
