1, Red Shrimp: Ku Shrimp, weighing about 10- 19g, Grade Four Shrimp, weighing about 20-29g, Grade Three Shrimp, weighing about 30-39g, Grade Two Shrimp, weighing about 40-49g, Grade One Shrimp, weighing more than 50g. 2. Macrobrachium nipponense: Macrobrachium nipponense, weighing about10-14g; Macrobrachium nipponense weighs about15-19g; Macrobrachium nipponense, weighing about 20-29g; And Macrobrachium nipponense weighing more than 30 grams.

First, crayfish are large, medium and small.

1, lobster species

(1) red shrimp: the body length is about 50-90mm, the weight is about 15- 100g, and the appearance color is crimson, red or brownish red.

(2) Macrobrachium nipponense: the body length is about 15-90mm, the weight is about 10-50g, and the appearance color is cyan or cyan.

(3) Library shrimp: crayfish that are not suitable for breeding or commercial shrimp.

2, specification classification

(1) classification method 1

① Red shrimp: bitter summer, weighing about10-19g; Grade 4 shrimp, weighing about 20-29g；; ; Third-grade shrimp, weighing about 30-39g；; ; Secondary shrimp, weighing about 40-49g；; ; First-class shrimp, weighing more than 50g.

② Macrobrachium nipponense: bitter shrimp, weighing about10-14g; Shrimp, weighing about15-19g; Macrobrachium nipponense, weighing about 20-29g; ; Macrobrachium nipponense, weighing over 30 grams.

(2) Classification method 2

① Red shrimp: Xiaohong, weighing about 2-4 yuan; Medium red; The weight is about 4-6 yuan; Bright red, weighing about 7-9 yuan; Red shrimp weighs 1 or more.

② Shrimp: Xiaoqing, weighing about 2-4 RMB; Zhongqing; The weight is about 4-6 yuan; Daqing, weighing about 7-9 yuan; Shrimp weight 1 above.

2. What do you mean by 2-4 yuan for crayfish?

1, crayfish 2-4 money refers to the weight of crayfish, not the price of crayfish.

2. The conversion relationship between money and gold, and between two and grams is as follows: 1 gold = 10 Liang = 100 money =500 grams.

3. So 2-coin crayfish refers to 10g crayfish, 3-coin crayfish refers to 15g crayfish, and 4-coin crayfish refers to 20g crayfish.

4. At present, crayfish on the market are divided into three specifications: 4-7 yuan, 6-9 yuan and 8 yuan. Among them, crayfish from 4-7 yuan are suitable for making shrimp balls, crayfish from 6-9 yuan are suitable for making braised prawns, and crayfish above 8 yuan are suitable for making steamed shrimps.