Agree totally with above, I am afraid that posts with this sort of question may get a little flamed as you need to read the stickys first.
If you want to keep rays then this is the forum for you, there are loads of great people on here and you can learn a lot from the threads.
Rays need BIG tanks - 200 - 300 gals min for an adult, probably much more than that.
Big filtration, big water changes and a big budget for food as they eat all the time.