What's wrong with my fishy?

Can anyone identify the problem my cardinal fish is having. It's not the first time I've seen this in a fish and I have no idea what the problem is or if it's treatable. He isn't swimming right and his mouth is stuck open. It's the thing with his mouth that I'm asking about. It's now open 100% of the time and I know he will not survive long like this.

 

I think the poor little guy is suffering from Mouth rot. The mouth tissue has been destroyed by bacteria, leaving a gaping hole for a mouth.
The mouth tissue will not regenerate making it very difficult for the Tetra to eat.

 

I think the poor little guy is suffering from Mouth rot. The mouth tissue has been destroyed by bacteria, leaving a gaping hole for a mouth.
The mouth tissue will not regenerate making it very difficult for the Tetra to eat.

Agreed. I would consider euthanizing him because he won’t heal

 

oh no, that's horrible! What would be the best way to euthanize? I never euthanized a fish before but I know this could turn into a week of suffering.

Also, is there something that can be done to prevent something like this from happening?

 

oh no, that's horrible! What would be the best way to euthanize? I never euthanized a fish before but I know this could turn into a week of suffering.

Clove oil.

 

Where do I get it and what do you do with it?

 

Where do I get it and what do you do with it?

I’m not sure how you use it. I’ve never dealt with tumors or anything that I can’t treat so thankfully never had to euthanize.