People are telling you it would die in the winter but the truth is it would die in a week. This pet was surely abandoned in the past 48 hours and that's why this is so rare.
They are hyper adapted to the water cycles, nutrient profile, and pH levels of the Xochimilco lake system in Mexico city and were taken care of by indigenous people for thousands of years. They have never survived anywhere outside of these lakes
They used to live in some others areas too. I once visited some places in the sierras close to Queretaro and while we were walking along the river a local guide told me he hasn't seen one in a decade but he used to see them regularly when he was a teenager.
Having said that there are surely a lot of factors that would make its survival impossible in wales given how hard it is for them to survive in their original ecosystems.