It is difficult for seawater aquarium fish to live in freshwater, and it is also difficult for freshwater aquarium fish to live in seawater. Therefore, the prerequisite for the breeding of seawater aquarium tropic fish is to fully understand the characteristics of seawater.

Seawater ornamental fish have higher water temperature requirements than freshwater tropical fish. They are very sensitive to changes in water temperature, so they can adapt to a narrow range of temperature changes. The water temperature of natural seawater is about 25-28°C, and the daily temperature difference of water temperature varies little. The seawater temperature in the aquarium tank should be controlled at 27-28°C, and the daily temperature difference of the water temperature should be controlled at about 1°C.

In the seawater ornamental fish aquarium, live corals, sea anemones and other invertebrates are raised at the same time, so the water temperature suitable for their growth is 26-30°C. If the water temperature is higher than 30°C, the life of the coral will be affected; if the water temperature is lower than 25°C, the vitality of the coral will be weakened and even die, and it will also affect the health of seawater aquarium fish. Therefore, ensuring the stability of sea water temperature is a prerequisite for keeping a good seawater ornamental fish and coral.