How to judge the health and quality of prawn fry from the appearance?

With naked eyes, the body is fat, the appendages are intact and not red, the body has no white spots and deformities, the muscles are full and transparent, the gastrointestinal tract is full of food, the movements are lively, the body is straight when swimming, the swimming ability is strong, the front two must always be together, and the group size is neat. These are good seedlings. If the observed shrimps are thin, they can't swim upstream when swimming downstream, their limbs are incomplete or red, their shells have white spots, their muscles are turbid and their balls are of different sizes, these shrimps are unhealthy and sick, so don't buy them.

High-quality shrimp larvae of Penaeus vannamei should have the following characteristics:

(1) vitality

Shrimp seedlings are uniform in size, transparent in body color and strong in vitality. Healthy seedlings are sensitive to external stimuli. When knocking on the container, they should jump away quickly without sinking, have strong jumping ability after leaving the water, and have obvious clustering after stocking. (2) The specifications are moderate

The shrimp seedlings are 0.8 ~ 1.2 cm long. The tentacles of shrimp seedlings should be strong, move forward together, the tail fan should be fully opened and the abdomen should be longer. (3) Body surface

The surface of shrimp seedlings should be clean, free from parasites and damage. Healthy shrimp larvae have complete limbs, strong body, smooth body surface, no parasites, no white spots on the head and breastplate, and no black gills. Muscles are transparent, hepatopancreas is dark brown, intestines are clear, and there is no broken beard, red tail and red body. (4) Normal food intake

Shrimp seedlings have a strong appetite and the phenomenon of grabbing food is obvious. After feeding the bait for a few minutes, food balls can be seen in the stomach, indicating that the shrimp seedlings are healthier. Shrimp seedlings have full stomachs and are orange-red, and the ratio of abdominal muscle width to intestinal width should be greater than 4∶ 1. (5) Swimming

In the static state, most of the shrimp seedlings are in the undercover state, and there is a phenomenon of top water after being stimulated by water flow. Direct swimming, fast speed and obvious directionality. Don't swim in circles. When stirring water, swim against the current. When the water is still, you should stick to the wall instead of stopping in the center of the container.