Reticulated ray hiding more than normal

I have had my ray a month and a half and he normally rests on the bottom changing places every hour or so. I put a fresh bunch of black worms in Wed morning he jumped right on one clump and pretty much ate the whole thing but since then he has hid pretty much in the same spot not moving I took a net and put it next to him in order to get him to move to a diff spot. After he moved he dug himself down in the sand until he isn't even visible. Is this normal or should I be worried?

Not yet, but our water hasn't been off in a very long time. Could a very large meal have anything to do with it?

We do weekly water changes, I plan on testing my water and doing a water change tonight I have been working the last few days and haven't had a chance to test the water. I haven't seen any aggressive behaver for the last few weeks when I fist got him I had to rehome a couple of fish for inconbatablity but all my other fish seem to be fine with him now

Just check water AMM 0 nitrite 0 nitrate 10-20 going to do a water change any other suggestion

Turn my sand at least once month so I don't think it could be that my ph is 7.8-8