As for the color of fish, it is suitable to raise gold and black, black, blue and gray. Compared with photosynthesis in the air, these colors will reflect harmful light and keep the gas field in a clean space, which is more conducive to the health of fish. If you keep red, green or purple fish, it is generally not recommended to keep goldfish of these colors because of their strong ability to absorb radiation, which is not conducive to their reproduction.