In addition to what AC has said, there are a few species to stay away from and some that fair better than others. For instance, I would recommend a california stingray, a cortez stingray, or a yellow stingray. Each one of these listed has an excellent track record for aclimating to aquariums.
On the other hand, the blue dot stingray does not do well at all in aquariums. They are probably one of the most beautiful of the stingray species, and are readily available. Tom most aquarists- including seaworld, they have a difficult time keeping them alive.
This is another basic piece of informaiton that I would like to provide you if you do decide to get a ray.