If you are monitoring the weight of your turtle and know they have gained weight then there's nothing too much to worry about. You could try hibernating the turtle but only try hibernation if they are a species that does and the turtle is a health... read more
Ensure that your turtle gets enough exercise; by providing a large and complex habitat, you will encourage your pet to exhibit natural foraging behaviors. Provide a varied diet, but refrain from feeding animal proteins to herbivorous species, which can cause nutritional problems in addition to obesity. read more
If you do choose to put more than one turtle in the same tank, make sure that each of the turtles has its own hiding place. Another thing to look out for is the possibility of breeding. This applies to having a male and female together. read more