Help with mystery problem

-I was out herping yesterday along some woods with a canal here in good 'ole Florida when I noticed a turtle flipped on his back stuck in a mud flat next to the canal, I raced over to find a Florida Red Belly, 10" male covered in a mass of insects including leeches but still alive. I being the animal lover I am flipped him over and with my insect tongs pulled all the critters off of him. I love Red bellys so I brought him ome to check him out and noticed that he seems to be full of gas or something, he can't stay on the bottom of the tank and it seems its his rear end that has the problem. I also noted that he is the most algae covered critter I have come across, even between his toes! rofl.gif I named him hairy! LOL I know with sea tutles they can get a gas build up and have the same problem so I was wondering what do you all think? Any helping him?

Well gas is a possibility, fluid in the lungs is another.

Raise the water temperature to around 80 F and provide an easy to access basking spot that gets 90 - 95 F.

Keep the water meticulously clean.

See if the turtle balances out better in the next few days.

If not a vet is an option.

Will it eat? (try fruits water plants, dark green vegetables and maybe cooked fish)

It could have been hit by a car, or dropped by a predator....or tossed by some idiot humans.