Seawater is the key to the success or failure of breeding marine ornamental fish. Before raising fish, first prepare good quality seawater. There are artificial seawater and natural seawater that can be used to breed seawater ornamental fish.

Thousands of creatures are bred in the ocean. The composition of seawater is an important condition for the growth of marine fish. Most of the seawater is sodium chloride, and the proportion of trace elements in the seawater is less than 1%. However, due to biodiversity and other reasons, they are very important for fish. The proportion of seawater components in all seas of the world is about the same, only the salinity is different. The salinity of the Pacific Ocean and the Atlantic Ocean is about 34‰ to 36‰, the Mediterranean Sea is 37‰, the Red Sea is over 41‰, and the Black Sea has a salt content of only 15‰ to 18‰.

The best way to take natural seawater is to take the water from the outer sea or select the seawater near the rocks. Do not take water from beaches, estuaries, and harbors. Seawater at high tide is better than seawater at low tide. Do not use seawater after heavy rain and typhoons, because there are many animal and plant plankton in the seawater at this time. After the seawater is taken, plankton will die due to lack of oxygen. Take the sea water and put it in a plastic bucket, and put a lid on it immediately after taking it.