Why are some species of turtles in the pet trade and not others closely related ?

Question

And only one of the tree African Hinged turtles is regularly in the pet trade, and the Red Eared Slider is much more common than the yellow bellied. Why is this perhaps?

Answer 1

Most of the turtles that you see in a pet store are wild-caught. Therefore, the species that you see in a pet store are more likely to be common species which are not protected in their places of origin.

Captive bred turtles are usually sold directly by the breeders, rather than pet stores, due in part to the four inch law. Most turtle species are not being bred in captivity, at least not in large numbers. This also limits what species are available.

Answer 2

turtles can carry salmonila, they are ilegal in some states because of that and most pet stores only carry red eared sliders