Question

Why do fish go deep water during daylight ,,

Answer 1

During daylight, the temperatures on the surface are likely to get higher. This affects the oxygen content of the surface waters because the warmer water gets, the lower the oxygen content. For this reason, fish goes deeper in the water where the oxygen content is higher.

Answer 2

The shallow water is warmer during the day due to which it has less dissolved oxygen. So the fish tend to go in deep water during the day time.