Solutions to fish farming without an oxygen pump:

1. Increase the frequency of water changes. You can reduce the rate of water contamination and increase the amount of dissolved oxygen in the tank water by increasing the frequency of water changes. When changing the water, oxygen from the air will enter the water in the fish tank.

2. Plant some aquatic plants. You can plant an appropriate amount of aquatic plants in the tank, and place the fish tank with aquatic plants in a place with slightly better lighting, so that they can use photosynthesis to synthesize part of the oxygen and provide it to the fish.

3. Reduce the stocking density. Appropriately reducing the stocking density and reducing the number of fish in the fish tank can reduce the consumption of oxygen in the water.

4. Lower the water level in the fish tank. You can make the water in the fish tank as shallow as possible, so that the dissolved oxygen in the water will be even and there will be more oxygen at the bottom of the fish tank.

5. Make the mouth of the fish tank larger. If the cylinder mouth is large, the contact surface between water and air will become larger, so more oxygen will be dissolved into the water.

6. Keep the bait clean. If the bait fed is not clean, the water quality will be deteriorated, which will increase oxygen consumption.