4 cm have adapted to the external environment, their physique is still relatively fragile, and the breeder should try his best to keep the water temperature stable. If conditions permit, the water temperature can be kept between 20-26 ℃. Because in this range, their appetite and activity are the highest. At this stage, Lanshou fry are sensitive to the change of water temperature, so breeders should control the temperature difference within 2 ℃.

Although the requirements for water quality are not high, they are sensitive to environmental changes, so breeders should not only keep the water quality clean at ordinary times. Attention should also be paid to the stability of water quality. The amount of water should not be too large, and the temperature difference between new water and old water should not exceed 2 ℃.

4 cm Lanshou fry is at a critical stage of development, and breeders can feed them more animal feeds, such as bumper shrimp, red worms, yellow mealworms, bread worms, lean meat, animal viscera, etc. The frequency of feeding can also be higher, feeding 3-4 times a day, and feeding 6-70% full each time. Because they are now small, breeders need to chop up food when feeding them.

Lanshou fry will start to develop color and start about 3 months after birth, so breeders need to bask them in the sun every day. It can not only help them synthesize pigments, but also sterilize them. But you can't bask in the sun for too long, just 2-3 hours a day.