I don't know their age, but they are approx. 4-5" disc width.
I am going to be keeping rays only...no other fish in the tank. The owner of the LFS fed them for me while I was there and they were eating frozen bloodworms pretty aggressively, so I suppose they are acclimating well. They have only been at this store for about a week. No idea how long the wholesaler had them....probably not too long.