Ruby fish can breed. Generally speaking, female ruby fish can be used for breeding when the body length reaches about 10cm. Males can be used for breeding when they are 8-9cm in length. To reproduce, it is necessary to first select some female fish with a body length of more than 10 cm and a swollen abdomen and male fish with a body length of more than 8 cm as broodstock, and put them in a larger fish tank.

The breeding cycle of ruby fish is very short, only about 20 days. Under favorable environmental conditions, it only takes 20 days from the first spawn to spawn again. If the broodstock is not allowed to hatch the eggs during reproduction, and the eggs are hatched artificially, then this time can be shortened to about 15 days.