What are the important conditions for raising marine fish?

There are many chemical components in natural seawater, mainly including sodium chloride, potassium chloride, magnesium sulfate and dozens of kinds of iron, lithium, iodine, aluminum, bromine and strontium. If these chemicals are fully mixed together in a certain proportion, convenient artificial seawater salt can be made. When in use, as long as artificial seawater salt and water are mixed in a certain proportion, artificial seawater closer to natural seawater can be made. At present, the artificial seawater salt produced in China is composed of sodium chloride, magnesium sulfate and potassium chloride in the ratio of 3: 2: 1, accounting for 90% of the artificial seawater salt composition, and 10% is composed of 20 kinds of trace elements, while the artificial seawater salt produced abroad is composed of 40 kinds of trace elements.

The use effect of artificial seawater is closely related to the quality of artificial seawater salt. The more complete the composition of artificial seawater salt, the more reasonable the proportion, the closer the prepared artificial seawater is to natural seawater, and the better the quality of artificial seawater. Marine ornamental fish live in such artificial seawater, and the stronger their adaptability, the higher their survival rate. The key to the quality of artificial seawater preparation is to select good quality artificial seawater salt first. At present, there are many kinds of artificial seawater salts sold in the market, both foreign and domestic, which can be carefully selected according to the characteristics of marine fish to be raised. The following is the formula of artificial seawater introduced by foreign data, with salinity of 3.34%, which is suitable for raising ornamental fish in seawater.

Mocleden artificial seawater formula (salinity 3.34%)

Nominal fractional unit: gram/liter of water

Sodium chloride Nacl 26.726

Magnesium chloride Mgcl2 2.26

Magnesium sulfate magnesium sulfate 3.248

Calcium chloride CaCl2 1. 153

Sodium bicarbonate NaHCO3 0. 198

Potassium chloride KCl 0.72 1

Sodium bromide NaBr 0.058

Boric acid 0.058

Sodium silicate 0.0024

Sodium silicate na2si4o90.00 15

Phosphoric acid 0.002

Al2cl60.0 13 aluminum hexachloride

Ammonia NH3 0.002

Lithium nitrate LiNO3 0.00 13

The water source for artificial seawater preparation is mainly self-provided water. Tap water will dry for a week, and then use it after the chlorine in the water evaporates. Or tap water is passed through an ion exchange resin filter, and the filtered water source is used to prepare artificial seawater, which is the most commonly used method for preparing artificial seawater.

The mixing amount of artificial seawater salt is determined according to the salinity of seawater. Natural seawater salinity is 3.4-3.5%, artificial seawater salinity is controlled at 3.0-3.3%, and artificial seawater salinity is slightly lower, which can reduce the osmotic pressure on the body surface of marine fish and eliminate the tension of marine fish. The salt content of artificial seawater is 3.0%, that is, 1000 kg of water contains 30 kg of salt. Then it is necessary to mix 3 kg of seawater salt with 100 kg of fresh water to prepare artificial seawater with salinity of 3.0%. The proportion of seawater in marine ornamental fish culture should be kept at 1.022- 1.023. The specific gravity and salinity of seawater are closely related to the water temperature. Only when the water temperature is constant will the specific gravity and salinity of seawater be stable. As can be seen from the following table, when preparing artificial seawater, it is very inconvenient to measure the water temperature first, then get the salinity from the table and calculate the amount of seawater salt.

Do not use metal containers in the preparation of artificial seawater. Glass jars, plastic or nonmetallic containers can be used when changing water in the future. Artificial seawater must be prepared 24-48 hours before use.

The step of preparing artificial seawater: put the water source into the aquarium of marine fish, calculate the required amount of artificial seawater salt according to the water quantity, directly dissolve the artificial seawater salt in the aquarium, and then start the aeration equipment and water quality circulating filtration equipment to make the water in the aquarium become artificial seawater. The newly prepared artificial seawater is unstable and turbid. The water quality should be measured every 12 hours, and the proportion of artificial seawater should be maintained at 1.022- 1.023 by mixing water or adding seawater salt. Generally, after 48 hours, the water color in the aquarium is clear and the water quality is stable. Using water quality testing agent, try to adjust artificial seawater to a reasonable range.

In the aquarium of seawater ornamental fish, it usually takes 15 days to a month for the biochemical filtration system of artificial seawater to be put into operation formally. Therefore, the cultivation of marine fish should be carried out after one month. The stocking quantity of marine fish should be gradually increased from less, and only when the biochemical filtration system of water quality is fully started can the stocking quantity of marine fish be stabilized. After the artificial seawater is prepared, the position of the water surface can be marked with lines, which is convenient for changing water after day.