According to the lip characteristics of the fish, you can determine which layer of the fish it belongs to. If the lower lip of the fish is slightly longer than the upper lip, it is the upper fish. For example, the lower lip of Mary fish is slightly longer than the upper lip, which belongs to the upper fish. In addition, according to the distribution of fish in the waters, they can also be divided into upper, middle and lower fish. Different fish like to stay in different layers of water. Mary fish often move in the upper waters, almost not involving the middle and lower waters, is a typical upper fish. Either way, Marlies are pelagic fish.
Mary fish is smaller, the selected fish tank volume does not need to be too large, just to ensure that it has enough swimming space. However, the fish tank can not be too shallow, it is best to ensure that the depth of more than 30 centimeters, so that each layer of water will have at least 10 centimeters of depth. If the depth of the fish tank is not up to the requirement, the area of each water layer will be very small. But Mary fish belongs to the upper layer fish, each water layer is very shallow, will cause it to contact the middle and lower waters, even needs to stay at the bottom of the tank. This is extremely disadvantageous to the fish which often swim in the upper waters. Therefore, the depth of the fish tank should be at least 30 centimeters, otherwise the water layer where the fish often stay will change, which is not conducive to their normal life.
