It always saddens me to see wild creatures, not bred for domestic life couped up in cramped spaces, awfully cruel. In terms of space in relation to size, what would you want for yourself in comparison??? Think of its natural habitat, limitless space and lots of other turtles/terrapins He's living a lonely, isolated and cramped life. Imagine yourself stuck in a tiny single room with no company
It would be better to take him to a zoo where they have breeding programmes and expert advice on how they should be looked after, and he/she would have plenty of space, an ideal environment and lots of friends with a choice of mates. Bear in mind that some of these creatures are also endangered species.
Probably not what you want to hear but just my 2p worth