So, yep, I'm surrounded by deep water, hell I'm standing in some deep water, but not so deep that I'm swimming.
Six inches either way and my triathlon swimming skills would be put to good test. A couple of times it was close too I might add.
Notice how all the fish are in front of all the submerged branches on the other side. This is because the flow is channeled that side, the flow of the water is broken up by submerged branches and there is are overhanging branches nearby.
Their dinner is brought to them, they don't have to exert a great degree of effort and they feel safe. Perfect.