The biggest tank you can attain, afford, and fit in your house, would be the best choice. I guarentee you that once you have 1 ray, you will want another one or 2.
So the bigger tank the better, Even though you will spend a lot of money initially you could always get slowly some of that money back by captive breeding the stingrays, and selling the pups!
So the bigger tank the better, Even though you will spend a lot of money initially you could always get slowly some of that money back by captive breeding the stingrays, and selling the pups!