Join Date: Jan 2002
Location: Vinson Massif, Antarctica
Almost every case of shell deformations is like shaggy said, from lack of calcium. Lack of calcium is not necessarily immediately attributable to diet though, but they should be fed a good variety of worms, insects, fish, turtle pellets like ones made by Reptomin, and so forth. Most problems I see are due to lack of UV lighting. The vitamin D they aquire from UV lighting (in the wild from sunlight) is absolutely necessary for the proper synthesis of calcium in their body. Without it, their body can't make use of the calcium they ingest.
With fluorescent style UV lights, they need to be no more than a foot above the turtle itself and can't be blocked by glass or plastic, as that cuts out most of the UV rays. They need a place where they can get entirely out of the water to bask and dry off. Always being wet can sometimes contribute to bacterial issues, like shell rot. Over the basking area, a heat lamp should be placed. That lets them get out of the water to adjust their body heat as necessary, and go back into the water when they don't need it. All painteds, cooters, and sliders need this kind of setup.
I have actually seen unexplained shell deformations as well, in animals that have proper UV , adquate heating and diet. Sometimes it can be hard to figure out the cause, and might be worth talking to a vet about.
She sits in her corner, singing herself to sleep.
Wrapped in all of the promises, that no one seems to keep.