Tropical fish cannot be released into rivers. There are two reasons why it can't be released. One is that tropical fish can't adapt. Most areas in China are not tropical, so the water temperature can't be kept at a high level all the time. When the temperature is low in winter, the fish will freeze to death. The other is that tropical fish are many exotic species, which will destroy the local ecological environment once released, thus affecting the survival of local aquatic animals.

1. Feeding: Pay attention to feeding first when raising tropical fish. Most small tropical fish are omnivorous, and there are many things to eat, usually with fish food. However, some of the large tropical fish are carnivorous, so they must eat small fish and shrimps, and they are not allowed to feed fish food.

2. Change water: In order to ensure the health of fish, change water regularly. There is generally no fixed period for changing water. According to the maintenance of water quality, if the water quality is not well maintained, it should be changed once every three to five days, and if the water quality is good, it can be changed once a week or two. Don't change water too much at a time, so as not to irritate the fish.

3. Temperature control: Because it is tropical fish, it has certain requirements for water temperature. Usually, the water temperature for raising tropical fish is higher than 20 ℃, but this is only the minimum standard. In order to ensure the growth of fish, the water temperature should be maintained at about 22-24 ℃, and some even need 26 ℃, so the temperature should be controlled by heating rods.