Torch Bubbles

[Paul28]

Anyoe know why my torch stomachs are bubbles thay have been like this for around 6 months it is very healthy so im not shur why its doing this for so long, its size is around 9 to 10 inch circle, lighting over it is perfect for what it is :confused:
http://img338.imageshack.us/img338/1765/62377925cw1.jpg