My Green Fire Tetra Has a ZIT!?!?

[MuddyWaters]

What is the white thing sticking out the side of my tetra? He's swimming fine and otherwise looks healthy. I see no issues on my other fish.

 

[GaryE]

it looks like a large cyst. That can come from a lot of reasons, and really, all you can do is watch it and hope it goes down.