Is this mouth rot?

[Sir Guppy]

I was watching my new Black Phantom Tetras, and saw this on one of their mouths:

 

[Naughts]

If it's new it might have swum into the glass. Lots of water changes and close monitoring - repost if it looks any worse.

 

[Sir Guppy]

Thank you.
Yesterday I put in some API Salt and preformed a minor water change today, and went away.
I will keep an eye on it though.

 

[GaryE]

Those bumps are common. They fight a little, mouth wrestling, and they bump things. With regular maintenance, they go away.

 

[Colin_T]

Little bump and nothing to worry about. Clean water should help it clear up.

Columnaris (mouth fungus) normally starts on the top lip and spreads up and over the face within a couple of days. The fish usually dies within that time.

The bump on the bottom lip is excess mucous covering a sore.