Just a little update. My Ray is doing very well! Eating nicely and getting along with tank mates. One mistake I made was thinking I would keep him on a black pond liner. He darkened up to blend in to the point he looked terrible. I decided I would use a thin layer of sand on the bottom to hopefully color him up. Here is a picture of the sand I used and a picture of the ray hiding in it for the first time. Its been about 4 days since I added the sand and my Ray has changed drastically! I will post more pics of what he looks like now soon.
https://imgur.com/a/HhfOqww
https://imgur.com/a/HhfOqww