Guppy Has Growth On Belly - Help!

I have a young guppy that I believe to be a male, that I’ve notice swimming in one spot, hiding in a barrel for the last couple days. Tonight I notice a white-ish pink ball like thing just in front of his bottom fin on its belly. Help???

 

That could be a poop... Can you get a picture?

 

 

 

 

Can someone confirm it’s a male??

 

Oh, it's definitely a male. And he's a bit skinny.
Could you make a better photo of the ball like thing? The current pictures aren't showing it clearly...

 

 

Do I feed it a pea? Salt bath? I have it separated in the tank. Do I need to quarantine? Tank water checks out. There are 3 other guppies and two mystery snails in it that all seem fine.

 

It's still hard to tell whether this is a bulge or a parasite of some kind. Did he always had this? For if that would be the case, it might be a undeveloped twin. It happens from time to time that a siamese twin is born but just one will develop as a normal fish and the other remains some kind of a bulge. If that's the case, it won't hurt him.
Have you observed if it's bothering him?

 

Never had it before.