Have you ever encountered an ornamental fish suffering from printing disease?

Printing disease, also known as "skin rot disease", is a bacterial infectious disease caused by the infection of injured fish by the punctate subspecies of Aeromonas aerogenes. Presumably, many fish friends have never encountered it. Goldfish and koi, which are mainly harmful to individuals, can be infected from fish species to parent fish, especially parent fish, many of which are improperly operated, causing fish injuries and being infected with pathogenic bacteria.

The disease can occur all the year round, but it is easy to occur in summer and autumn. It is beneficial to the occurrence and prevalence of the disease when the water temperature is 28-30 ℃. Fish of all ages can be infected, which mainly harms the adults and parent fish of more than 1 year old. There are sporadic epidemics all over the country, and the infection rate in infected fish ponds can be as high as more than 80%. A large number of deaths rarely occur, but seriously affect the growth, reproduction and commercial value of fish.

Main symptoms

The disease mainly occurred in the trunk behind the dorsal and ventral fins, followed by both sides of the abdomen or near the anus, and a few occurred in the anterior part of the fish body. In the early stage of the disease, the affected skin and muscles became inflamed, then began to rot, the middle part of the scale fell off, and the boundary between the focus and the surrounding tissue was obvious. The decaying epidermis disintegrates and falls off, exposing the dermis, showing erythema, the diseased place is irregular round, oval or oval, and the edge is congested, as if it was covered with a red seal on the skin of the fish, so it is commonly known as "printing disease". With the further development of the disease, the diameter and depth of the lesions gradually expanded, forming a small pot-shaped hole. In severe cases, the muscles were worn out, exposing bones and internal organs, and the diseased fish died quickly. Diseased fish have loss of appetite, slow swimming, weak body, severe eyeball collapse, and eventually die of exhaustion.

Main points of diagnosis

According to the epidemic characteristics of the disease and the special diseases of diseased fish in specific parts, a preliminary diagnosis can be made.

Precautionary measures

Strengthen the feeding and management so as not to hurt the fish.

Reasonable feeding can provide sufficient feed for fish and enhance their disease resistance.

Keep the water quality fresh and clean, often add new water, regularly sprinkle 1 gram of bleach per cubic meter of water in the whole tank to disinfect the water.

Treatment measures

Scrub the wound of the diseased fish with hydrogen peroxide to remove the rotten tissue, then scrub the affected area with potassium permanganate solution, generally adding 1 gram of potassium permanganate for every 500 grams of water; at the same time, bathe the diseased fish for 10 minutes with a solution of 2.5 grams of erythromycin per cubic meter of water for 10 minutes, once a day for 3 days until the condition improves. Each ornamental fish can also be injected with 100000 international units of penicillin or tetracycline hydrochloride. Improve feeding and management, increase nutrition for diseased fish and enhance their resistance.

Matters needing attention in diagnosis and treatment

When using antimicrobials to treat the disease, we should choose drugs that are sensitive to pathogens. However, taking into account the differences in drug resistance of local pathogenic strains of the disease, it is best to use drugs after drug sensitivity test of the isolated pathogenic strains under conditional conditions to ensure the therapeutic effect. In addition, the selected drugs and disinfectants should be less irritating and corrosive to avoid secondary damage to fish wounds.

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