Disinfectants are the most commonly used drugs in aquaculture, used to eliminate or kill pathogenic microorganisms and other harmful microorganisms in the external environment. According to chemical properties, it can be divided into eight categories: aldehyde disinfectants, alkali disinfectants, acid disinfectants, salt disinfectants, halogen disinfectants, dye disinfectants, oxidant disinfectants, and heavy metal disinfectants. There are many species of aquaculture animals in my country, and the toxicity of different types of disinfectants to aquatic animals is quite different.

1.Bleaching powder

Calcium hypochlorite, the main component of bleaching powder, produces hypochlorous acid and hypochlorous acid ions with bactericidal power when contacted with water. Hypochlorous acid can also release active chlorine and nascent oxygen, thereby producing chlorination and oxidation reactions on bacterial protoplasmic proteins, exerting its bactericidal effect, and having different killing effects on bacteria, viruses and fungi.

2.Sodium hypochlorite

Sodium hypochlorite, commonly known as bleach, is a commonly used chemical disinfectant. It has strong poisoning power and does not have strict selectivity for organisms. However, this drug is not stable, and attention should be paid to active ingredients when using it. Its mechanism of action is the same as that of bleaching powder.

3.Sodium Dichloroisocyanurate

Sodium Dichloroisocyanurate has the same mechanism of action as bleaching powder, and produces hypochlorous acid and hypochlorous acid ions with bactericidal power in contact with water. It has a wide bactericidal spectrum and has a strong killing effect on bacterial propagules, spores, viruses, fungal spores, etc.

4.Trichloroisocyanuric acid

Trichloroisocyanuric acid, also known as strong chloroquine, has the same mechanism of action as bleaching powder, and its validity period is 4 to 5 times longer than that of bleaching powder. It has a significant effect on skin diseases, and has excellent effects on diseases such as fulminant fish disease, leukoderma, printing disease, and white-headed and white-mouthed disease.

5.Bromochlorohydantoin

Bromochlorohydantoin is a high-efficiency, broad-spectrum disinfectant. Its pH range is wider than that of conventional chlorine-containing disinfectants, and the killing effect is good. In water, it can continuously release active Br- ions and Cl- ions to form hypobromous acid and hypochlorous acid, and oxidize the biological enzymes in the microorganisms to achieve the purpose of sterilization.

6.Dibromohydantoin

Dibromohydantoin hydrolyzes relatively fast, can continuously release HBrO (active bromine) in water, and penetrate the cell wall of microorganisms to destroy bacterial proteins, resulting in irreversible oxidation and damage to the internal structure of the cells. Decomposition, and finally play a sterilization effect.

7.Chlorine dioxide

Chlorine dioxide is a strong oxidant. It is different from the action mechanism of general chlorine preparations. The activated chlorine dioxide produces new ecological oxygen with strong oxidizing effect under the action of hydrogen ions, which can quickly attach to microorganisms. The surface of the cell penetrates deep into the cell membrane of the microorganism, so that the microbial protein loses its vitality and achieves the purpose of killing the microorganism.

8.Formalin

Formalin is an aqueous solution of 40% formaldehyde, which has a strong pungent odor, can coagulate proteins and dissolve lipids, denature proteins, and has powerful broad-spectrum bactericidal and insecticidal effects.

9.Potassium permanganate

Potassium permanganate is a strong oxidant, its aqueous solution contacts with organic matter, can release new ecological oxygen, rapidly oxidize organic matter, make the active groups and sulfhydryl (— SH) is oxidized into disulfide chain (—S—S) and inactivated, thereby playing a bactericidal effect.

10.Quicklime

The main component of quicklime is calcium oxide, which is a convenient, cheap and efficient disinfectant. When mixed with water, it generates calcium hydroxide and releases a lot of heat, which can quickly dissolve the cell protein membrane and make it lose its vitality, thereby killing the pathogens in the pool and the harmful organisms remaining in the pool. When used for sterilization and treatment of diseases, attention should be paid to the change of pH value of the water body, and it should not be excessive, because when the pH value of the water body is greater than 7.5, the quicklime can rapidly increase the pH value to form a strong alkalinity, which is easy to cause dead fish. Quicklime is highly sensitive to snakehead, juvenile M. rosenbergii, and larvae of M. rosenbergii, so it should be prohibited to use in production.

11.Sodium chloride

Its aqueous solution can be used as a hypertonicity agent, and the osmotic pressure of pathogens or their attached organisms can be changed by immersion method, so that the liquid inside and outside the cell will be out of balance and die or fall off from the anchorage. is widely used.

12. Povidone-iodine

Povidone-iodine is a water-soluble polymer compound composed of molecular iodine and PVP that can slowly release iodine, and maintain a dynamic balance between the two. Its bactericidal activity is the affinity of the bacterial membrane provided by the surfactant PVP, and the iodine contained in it is combined with the cell membrane and cytoplasm to oxidize or iodide thiol compounds, peptides, proteins, enzymes, lipids, etc., so as to achieve sterilization. the goal of. As a broad-spectrum disinfectant, it has different degrees of killing effect on most bacteria, fungi and viruses. It is mainly used for surface disinfection of fish eggs and aquatic animals.