IMPORTANT=unidentified hatchet fish problem=IMPORTANT

[alaniq]

My hatchet fish has physical symptoms but no behavioral. His mouth is black and some clear, reddish substance is coming out very slowly. None of the fish or items have injured him, and all tests are negative. Does anyone know why?

[Dave66]

Photo would of course be helpful but as all Characins, your hatchetfish have teeth, thus they are want to do a bit of sly nipping here and there. Just because you haven't seen it, does not mean that the hatchet wasn't injured by another fish.
Monitor the fish closely, as the clear red is blood. Is it otherwise eating and acting normally? How long have you had the fish? When was the aquarium established?
Tank size, water parameters and tankmates, please.

Dave

[alaniq]

That is true, but I just figured out that it actually isn't stuck to his mouth, it is stuck to his lower jaw! The substance has turned white, and there is no sign of blood or injury, because he is eating and acting normal. How long have you had the fish? The fish was bought from another person, but I have had it for almost a year. The aquarium is as old as the fish.
It is a 30 gallon tank. 48*18*12. Tankmates include 3 hi-fin tetras, a golden gourami, 2 kissing gouramis, two iridescent sharks, and small catfish, two small scissortails, and the hatchet fish himself.

[Northernguy]

A picture of your fish would be a huge help!
Your tank is a lot more than 30gal.Its at least 40+ !

[Lady Hobbs]

I agree with Dave. Mostly likely an injury from a bite or a decoration. Watch it to make sure it doesn't turn into a fungus. He should heal up quickly.