1. Egg taking: The female fish taking eggs are washed with clear water first, then disinfected with 5% salt water, and then the eggs are taken by laparotomy.

2. Egg washing and separation: After fish take eggs, immediately put the eggs into ice water at 0- 1℃, wash off blood water and filter water.

3. Salt water preservation: put the dried eggs into a fresh-keeping tank, stir with saturated salt water for 15 to 20 minutes, and drain the salt water.