help! talbone sticking out of toad

[lizarddude]

hey guys. i have 2 fire belly toads in a 10 gallon cage. they are in around 3 or 4 inches of water, with gravel about the size of a nickel or dime (around) and 2 or 3 centimeters high. they have a heater and a uvb lamp, and i clean the cage entirely about once a week. i give them filtered water that is treated for chlorine. the toad i am refering to is around 3 years old. he is fat, with skinny arms and legs and his talbone is pushing against his skin. i belive it is his tailbone because that is the only bone that is in that area. any help would be great. thanks!