Koi cannot be released because koi is a carp species that has been bred through long-term cross-breeding. After being released into the wild, it is extremely easy to hybridize with close relatives. In other words, koi will hybridize with natural carp in the wild. If things go on like this, the nature of Carp genes can mix, threatening the purity and survival of native carp.

Precautions for raising koi:

1. Water temperature: Although koi is a cold-water fish, it also has requirements for water temperature. The adaptable water temperature range is 2 ℃ - 30 ℃, but preferably at 20 ℃ - 25 ℃, and the sudden change of water temperature should not exceed 2 ℃ - 3 ℃, otherwise discomfort reactions will occur.

2. Water quality: Koi likes to live in a slightly alkaline, low-hardness environment, and the dissolved oxygen in the water must be particularly good. The digestive system in the water should be strengthened, and food residues and koi fish feces should be cleaned regularly.

3. Food: Koi is an omnivorous fish. In addition to the usual koi feed, general molluscs, higher aquatic plant fragments, benthic animals, etc., you can also make your own koi fish food. Some vegetables and fruits with high nutrients such as vitamins.