1. it is best

to keep a few fish in the fish tank. As long as the fish tank is big enough, there is no limit to the number of fish, one, six, eight, nine are all very good. Usually, there is a close relationship between the number of fish and the size of the fish tank. The bigger the fish tank is, the more fish can be raised. Otherwise, too high feeding density will not only reduce the dissolved oxygen, but also cause them to fight with each other, resulting in fish injury and death, causing unnecessary losses.

Luohan fish: Luohan fish is a common ornamental fish. It has a strong exclusiveness. Although it is very clever when it is young, it will attack all the fish around it when it grows up. So it is usually not suitable to raise other fish. This kind of fish has forehead beads on its head, even if only one is beautiful.

2. Arowana: Arowana is also a fish that cannot be polycultured. It has a large body and a ferocious temperament. It is a carnivorous fish. It cannot be polycultured with other small fish. It is best to put it in a fish tank alone. And even if they are of the same kind, if they are put together, they will fight to the death.

3. Betta: Betta is a kind of small fish. There are two kinds of fish, the Thai Betta and the Chinese Betta, all the year round. From the name, we know that it is very aggressive, so do not mix it with other fish, otherwise it will fight. Two male fighting fish can also fight, so only one is usually kept.