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?