I've had him about 5 days and he seemed to be doing great. Moving around a lot, exploring, and eating. At night he usually finds a spot on the back glass and stays there until morning when the lights change. Today however he hasn't moved once. He's been in the same spot on the back glass for about 24 hours. He's right up by the surface. Looks like an arm or two is above the water level and the rest of him is under. He seems to like to go near the surface. I can't imagine there's a lack of oxygen. I have a sump with wet/dry filter setup and protein skimmer. I did feed him a shrimp and he grabbed it right away. Just hasn't moved Am I overreacting? He has just been way more active up until the point.