Rainbowfish with mouth stuck shut

[lobstersrcool12]

Hello all,

I've been having some issues with one of my dwarf neon rainbowfish. The tank is heavily planted 30g, fluval 204 filters, 0 ammonia, 0 nitrite, <20 nitrates and has been established for years now. I have 3 other rainbowfish som khuli loaches and a school of ~10 ember tetras. Around a month ago I noticed that one of the rainbowfish was a little smaller and less colorful than the others (this was after I had had them for ~5 months). Upon paying closer attention I noticed the fish seemed to be struggling to eat, and would just push food around instead of actually opening its mouth to eat it. I did some water changes and added some aquarium salt, but over the last month or so the fish has slowly reduced in size (much skinnier than the rest of the rainbows). Other than the skinniness and difficulty eating the fish is acting healthy (ie. swimming around fine and getting excited for food). Seeing as the issue wasn't resolving itself, I put the fish into a quarantine tank and tried slowly increasing aquarium salt level. This improved liveliness in the fish, but it still wasn't able to eat. I have tried feeding bloodworms and garlic, and there are no issues with the fishes desire to eat/attempts, but the mouth remains shut. The last week or so I put the fish on an antibiotic treatment using furan-2 (although I don't see much evidence of mouth rot I figured I had to try everything). When the fish attacks food, the lower half of it's jaw juts out, flaring the gills, but the top part doesn't open. It is kind of heartbreaking watching the fish try so hard to eat. Could the jaw be broken and is there anything I can do about this? Thanks in advanced!

TL;DR - Dwarf neon rainbow fish mouth stuck shut, definitely has appetite but remains unable to eat and has slowly been reducing in size. Water change, aquarium salt, garlic, antibiotics have all been tried.

 

[Delapool]

Could it have rammed into tank glass?

 

[lobstersrcool12]

Possibly? The fish were never particularly skittish and I have the tank near a window so that natural light comes in before the tank light turns on, but it is still possible. The jaw doesn't look deformed compared to the rest of the rainbowfish, but it is pretty small so hard to tell, especially with the fish moving around all the time.

If it is a broken jaw do you know anything I can do?

 

[Delapool]

Unfortunately no solution that I know of.

Increasing salt would of been my ‘cure all’ try but sounds all has been done.

 

[Delapool]

If big enough fish, you could try looking inside mouth in case a stuck pebble.

 

[lobstersrcool12]

Thanks all for the replies. I went ahead and opened the fishes mouth (with a dulled toothpick) and didn't see anything in particular lodged down there. Couldn't manage an extra hand to take pictures unfortunately. The fish didn't really resist/bite down although I'm not sure if I would have been able to feel it. I'll continue feeding/dosing garlic in the hope that it is a parasite or something, but I suspect it may be a dislocated jaw and I'll have to euthanize. It is a shame that the fish is so relatively active/healthy otherwise.

How bad of an idea would it be to make a "stint" that will prop the fishes mouth open just a little bit so it can get food in? I could 3D print one or make it with fine gauge stainless steel wire? Lower half of the jaw seems be working fine (gill flaring and outward bulging of gullet). Any adhesive I could use without hurting the fish?

 

[Delapool]

Guess could try it? I don’t think I’ve ever heard of anything. Post back if you do?