Find out where the animals come from. Talk with other pet shops or even local conservation officers to find out if any complaints have been lodged against the dealer. Don't let your interest in a species help cause it to go extinct. Unwanted pets are often released into the wild. Most perish in a short time, either because they are tame and therefore not wary of predators, or they cannot cope with the long, cold Canadian winter.
Some individuals do survive and appear to even thrive in their new homeland.
That is a problem, because exotic species can cause a number of problems. First of all, exotic species compete with native species and may actually be able to displace some native species. Exotics may also bring foreign diseases that native species are not able to cope with. Although their importation to Canada is now banned, eggs are still imported. Red- eared Sliders are quite common now in the Great Lakes area.