It's been about a week since I put my yellow corris wrasse into the DT. He immediately buried in the sand but I have not seen him since. Checked overflow, floor, and sump. I was cautioned they can go under the sand for a few days if threatened but is a week normal? I did notice a few snail shells upside down near where he first buried himself with no foot visible anymore, could he be coming out at night and munching on snails? I don't mind if so, there are so many snails breeding in the tank I'm just worried about him.