PP has it right for what I meant. We weren't allowed to go underwater, like physically put your head under, in the stingray pool, but we could use the underwater camera under water (as in stick in under the water and snap a pic)
When I was there in January, they were telling people left and right not to go under. I think its a matter of people would try to swim if they went under, and since that water is so shallow and there's so many rays in the area, you'd end up kicking or hitting them. In the Coral Reef, the rays have more room to avoid you.