People have been feeding the fish here every morning for years and there's always a big shoal of striped sargos waiting for bread. The best time to see them is in the morning when the tide is low because the fish are hungry and the water is clear.
While it's technically illegal to feed them, there's always someone throwing in a few crusts. Stand in the water and they come right up to you.
To find the spot, look out for a small rock sticking out of the beach right in front of Luis Morote street. The fish are just to the left (south) of the rock.