Swollen Male Guppy

I noticed one of my male guppies has a swollen underneath. It appears more on the left then the right. He is the biggest out of the group of four. They are fed twice a day only a few flakes. The other three look normal.
I'm not sure if there's anything I can do to help him?

 

Is he always like that or has this happened suddenly?

If hes always like that (or it appeared gradually) then its just a lot of fat. Having "chests" like that is actually more common in male guppies because they are such pigs. My advice is to add a fasting day or two per week and make an effort to prevent him from getting more than his share of the food.

 

He normally is a little round but today I noticed the additional bump under him. I feed them at 8am and 6pm.
Should I fast the whole day or just one of the two feedings?

 

He normally is a little round but today I noticed the additional bump under him. I feed them at 8am and 6pm.
Should I fast the whole day or just one of the two feedings?

I would only feed once a day 5 days a week and fast the entire day 2 days a week (like friday and monday). This shouldn't be a problem, but it can be really unhealthy and will shorten his lifespan if you can't get him to slI'm back down to formal sized (stomach is flush with the gills)

 

Okay thank you