People often liken their first time diving to flying due to the feeling of weightlessness. There is no time when this feeling is more real than when diving a wall dive with the current. Try to imagine flying horizontally alongside a skyscraper but not being able to see the floor.
These are the anthias I referred to in the post the other day about groupers. You can imagine how many millions there must be on a huge reef wall just by looking at this photo. These clouds of anthias on Elphinstone in the southern Egyptian red sea attract large numbers of reef predators as well as dashing attacks by pelagic predators like jacks and trevally.
Other browsers will move along the wall in huge stacked shoals. These are henniochus wimplefish but tangs and surgeonfish are often seen moving in a similar way.
If you get close to the wall you'll pass an array of fascinating tiny critters that make up the diet of most of the reef fish but its important not to get too caught up in the little things. If you do you might miss the big boys passing by in the outside lane...