Strange Lump on Trigger - Need Help Diagnosing

[D3R3K]

I've had this blue throat trigger for about a month and he has been the picture of good health. Over the past week I've noticed a lump forming on one of his sides. I'm pretty sure it wasn't there a few days ago. The scales look completely normal, so I don't think it's a parasitic.

Any ideas what it is?

 

[HumbleFish]

Possible internal tumor? But whether it is or not, I wouldn't do anything about that except sit & wait.

 

[D3R3K]

Yeah, that's my plan. Thanks for weighing in.