. The zebrafish is the upper layer fish. It usually likes to swim in the upper layer of the water. Sometimes it is normal to see the zebrafish surface. It is worth noting that if the zebrafish that should rest frequently surface at night, it is mostly caused by insufficient oxygen in the water. The space of the fish tank is relatively small, and when the density of fish farming is relatively large, it is easy to have insufficient oxygen supply. When oxygen is insufficient, zebrafish will surface to get oxygen from the outside world. At this time, the zebrafish should be oxygenated to provide oxygen.
of upper and lower fish 1. Upper fish: Upper fish usually spend most of their time in the upper part of the water, occasionally jumping their heads out of the water. The lower jaw of the upper layer fish is longer than the upper jaw, and the mouth shape is slightly upturned.
2. Lower fish: If the dissolved oxygen in the water is sufficient, the lower fish can stay at the bottom of the water for a long time. When the dissolved oxygen is low, they will rise to the middle or surface of the water to absorb oxygen, and then dive to the bottom of the water. Most of the fish in the lower layer are feeding at the bottom of the fish tank, except for feeding, spawning, courtship and other reproductive activities, they usually stay quietly at the bottom of the fish tank. The upper jaw of the underlayer fish is longer than the lower jaw, and the mouth is downward.
