It is very likely that goldfish will lack oxygen when raised in a small fish tank, because the water body in the small fish tank is small and the dissolved oxygen in the water itself is not much. Moreover, if the water body is too small, the water quality will deteriorate faster. Poor water quality will also lead to a decrease in dissolved oxygen in water. Although goldfish's demand for oxygen is not very high, the low amount of dissolved oxygen in water will also lead to their lack of oxygen. When raising goldfish artificially, if you want to reduce hypoxia, you'd better change water frequently to ensure clean water quality. Because if the water quality is clean, the dissolved oxygen in the water will also increase. Moreover, there is more oxygen in the new water, which can meet the demand of goldfish for oxygen.

Whether goldfish need to use oxygen pumps depends on their living environment. If goldfish live in sufficient space and the water body is relatively large, they do not need to use oxygen pumps. Because goldfish does not require high oxygen, as long as the water is changed frequently, the dissolved oxygen in the water can be guaranteed to be sufficient.

If the feeding density is relatively high, the breeder needs to install an oxygen pump. Because of the high density of oxygen consumption, goldfish are prone to lack of oxygen. But breeders don't need to turn on the oxygen pump 24 hours a day, only need to pump oxygen for 2-3 hours a day, which is enough for them to absorb. In addition, the oxygen pump can also be turned on in rainy days or when the air pressure is low.