nguyendetecting
"Swim along with the snorks"
I've had cories for years and have had many spawns raised to adulthood. I've seen many cories float around above the gravel, hover in the middle of the tank, and just cruise along the surface. It just depends on the individual. I wouldn't be worried with them "standing" off the ground. But the fact that they have shortened or missing barbels I would be worried. They're probably hovering to keep their sore or hurt barbels from contacting the ground. I would change to sand or a smaller gravel. If you can't at the moment put a smooth piece of slate in the tank and see if they are gathering to that, the smooth slate will feel better on their barbels.