If he's bloated, he probably just needs to poop. Constipation is easy to treat. Don't feed him, that'll make it worse. Not to worry, he can go a few weeks without food. If you have any epsom salt laying around, you can give him a quick dip in that.
In a separate container (bowl, tank, whatever) add 1 Tbsp per gallon of Epsom Salt. Make sure you dissolve the salt before adding it to the water. You can do this by getting a clean cup, adding some salt then some really hot water and stiring it til all the salt is desolved (microwaving it is fine) THEN adding the disolved salt to your seperate bowl or tank. Don't forget water conditioner. :)
Make sure the water temperature is close to his tank temp when you place him in it. Leave him in for no more then 15-20 mins. This is called an epsom salt dip. Put him back in his tank and wait, he should poo out something pretty big soon enough. If it doesn't work, come back and we'll help if we can.
And don't worry, he'll be fine if he's just constipated.