There are many species of rodent fish, and different species of rodent fish enter the estrus at different times. They can only begin to reproduce after entering estrus. Normally, it takes two years for rats and fish to mature before they enter estrus, but some fast-growing species can start breeding when they are about eight months old.

Attention should be paid to the breeding of rats and fish that are too young, which will not only damage the body of parent fish, but also be extremely unfavorable to the development of small fish. When feeding rats and fish in breeding period, attention should be paid to animal feed as much as possible, for example, feeding them some live bait, such as nematodes, bumper shrimp, water fleas and so on. This kind of food is rich in a variety of nutrients, which is more conducive to their reproduction.

The life cycle of rodents is not long. After entering the breeding period, they can reproduce once a month, some fish can reproduce once every two or three weeks, and can reproduce 4-7 times a year. Their reproductive ability is relatively strong, and they can reproduce all year round and once a month under suitable conditions.

In the natural environment, rats and fish only reproduce once a year, probably at the intersection of spring and summer. They lay different eggs each time, ranging from a few eggs to several hundred eggs, and the number of eggs laid by different constitutions is also different.