Chemical fish ponds lack oxygen in rainy days in grade three.

First, the weather is hot and the dissolved oxygen in the water is reduced.

B, thunderstorm weather, atmospheric pressure is less than sunny days, (water vapor content in the air increases, atmospheric pressure decreases), atmospheric pressure on the surface of the pond decreases, and dissolved oxygen in the water decreases.

(2) Oxygen increasing method:

First, cooling down

B, use air pump (that is, aerator) to increase oxygen supply in the pond.