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How to judge the severity of fish gasping at the surface

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To judge the severity of fish gasping at the surface, the main criteria are the time when the fish begin to gasp, the location of the gasping, the size of the water surface area where they gasp, and the species of fish gasping. 1. Dark gasping. This generally occurs when it is already daylight but the sun has not yet risen; the fish move about on the water surface in the center of the pond and on the upwind side, and bursts of splashing water can be seen. At this time the dissolved oxygen content of the pond water is 2-3 mg/L, which is normal gasping. 2. Light gasping. This mostly occurs at dawn; the fish are on the water surface in the center of the pond and on the upwind side, while wild trash fish gasp at the pond edge.

To judge the severity of fish gasping at the surface, the main criteria are the time when the fish begin to gasp, the location of the gasping, the size of the water surface area where they gasp, and the species of fish gasping.

1. Dark gasping. This generally occurs when it is already daylight but the sun has not yet risen; the fish move about on the water surface in the center of the pond and on the upwind side, and bursts of splashing water can be seen. At this time the dissolved oxygen content of the pond water is 2-3 mg/L, which is normal gasping.

2. Light gasping. This mostly occurs at dawn; the fish are on the water surface in the center of the pond and on the upwind side, while wild trash fish gasp at the pond edge. The area is not very large, the gasping fish gather in schools, and when startled they quickly sink. At this time the dissolved oxygen content of the pond water is about 2 mg/L, which is also normal gasping.

3. General gasping. The gasping begins 1-2 hours before dawn. The pond fish are mostly concentrated in the middle of the pond, and the gasping area is relatively large. When undisturbed, the school of fish sometimes moves toward the edge, and when startled it quickly sinks. The wild trash fish at the pond edge are already in a state of severe gasping, and a small number of wild trash fish can be found losing their balance, but there are no dead fish. At this time the dissolved oxygen content of the pond water is below 2 mg/L, which is the limit of normal gasping.

4. Severe gasping. The gasping begins around midnight, and spreads from the middle of the pond toward the edge. Almost all the pond fish are in a state of oxygen deficiency, and they do not sink even when startled. Dead wild trash fish have already been found at the pond edge. At this time the dissolved oxygen content of the pond water is 1-1.5 mg/L. The situation is already very dangerous, and high-energy quick-release oxygen should be spread dry over the pond surface immediately.

5. Pond turnover. The gasping begins early and the water quality has already deteriorated; a foul fishy odor from the pond can be smelled on the bank. All the pond fish are gasping, breathing rapidly and swimming weakly, and the number of dead fish in the pond is found to be gradually increasing. If oxygen-increasing measures are not taken in time at this point, the pond fish are at risk of being completely wiped out.

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