Columnaris Management in Carp Fish: Disease Symptoms, Management, Prevention, Causes, Control, and Treatment

Columnaris disease is highly contagious; it can affect freshwater and saltwater fish. It is commonly known as cotton wool disease or saddleback disease. This disease leads to severe financial losses in fish farms worldwide annually. Although young fish are more susceptible to the disease, healthy and older fish can also act as carriers of the bacteria. The bacterium is present in most aquatic environments, making it challenging to control the spread of the disease.

Infected fish may exhibit various symptoms, including cotton-like growths on the body, fin rot, and lethargy. Effective disease management involves early detection, proper sanitation measures, and prompt treatment using antibiotics. Prevention measures such as maintaining good water quality, avoiding overcrowding, and regular health checks are also crucial to minimize the risk of infection.

Columnaris Management in Carp Fish

Causative Agents of Columnaris Disease in Carp Fish

Columnaris disease in fish is caused by the bacterium Flexibacter columnaris, which belongs to the family Flavobacteriaceae.
This bacterial infection can affect various fish species and is found in salt and fresh water. It can cause damage to the skin, fins, and gills of the fish.
One of the most distinct symptoms of columnaris is the development of a dark, raised lesion on the back of the fish, which can resemble a saddle.
The lesion can also cause the fish to develop a hump-backed appearance. This disease is highly contagious and can lead to severe economic losses in fish farms worldwide.

Species of Fishes Affected by Columnaris Disease

Columnaris disease can affect various freshwater and marine fish species, including rainbow trout, arctic char, catfish, salmon, bass, bluegill, carp, koi, tilapia, flounder, sole, sea bass, grouper, snapper, barramundi, eel, and tuna. In North America, channel catfish, blue catfish, largemouth bass, and fathead minnow are also susceptible to the disease. This disease impacts fish farms and aquaculture operations, leading to economic losses and decreased fish populations if not properly managed.

Spread and Transmission of Columnaris Disease in Carp Fish(SVC)

Flexibacter columnaris, the bacterium responsible for columnaris disease, is commonly found in aquatic environments, including water, mud, and plants.
The disease can enter an aquarium or culture system, including the water source, new fish, equipment, and other aquatic organisms.
Once inside an aquarium or Culture system, the bacteria can survive and multiply in biofilm.
Therefore, good hygiene and biosecurity measures, such as quarantining new fish, properly cleaning equipment, and using a quality water conditioner, are essential to prevent the disease from entering and establishing in the aquarium or culture system.

Symptoms and Signs of Columnaris Disease in Carp Fish(SVC)

Clinical signs of columnaris disease in fish include external infections with lesions on the body surface and gills.
These lesions may appear as whitish ulcerations or erosions of the gill lamellae.
Hemorrhages may also be observed in the affected areas. These signs are the result of the bacteria causing tissue damage and inflammation.
Columnaris disease affects a fish’s gills, fins, and skin, causing an infection that can be short-lived or last for a long time.
The fish may get a white or grey film on its body, which can kill the fish in severe cases.
Adult fish’s gills can get yellowish spots of dead tissue, leading to a buildup of gill lamellae and swelling.
The fish has small sores and pale skin mottled with a reddish tint. The sores are covered in yellowish-white mucus and can grow in the head and the tail.
When the gill filaments are looked at, there is a lot of damage and erosion. The filaments look brown and are covered with necrotic debris, which is made up of dead tissue and cellular waste that has fallen off the filaments.
The brown color of the dead tissue probably means that bacteria are making pigments or that red blood cells are breaking down.
Columnaris infection can also cause skin sores and damage to the tail fin.
The disease can spread quickly, and fish with it may show signs of pain like gasping for air, getting tired, and losing their appetite.

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Diagnosis of Columnaris Disease in Carp Fish(SVC)

Columnaris disease in fish can be difficult to diagnose, particularly if the infection runs internally with no external signs. However, there are several ways to diagnose the disease:
By imaging the surface of a bacterial culture or a sample obtained from an infected region, scanning electron microscopy (SEM) can identify the shape of bacteria.
Histopathological examination entails scrutinizing tissue samples under a microscope for pathological changes such as bleeding and gill congestion.
By detecting the presence of particular proteins or genetic material associated with the bacteria, molecular tests such as enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) can effectively diagnose columnaris.

Treatment of Columnaris Disease in Carp Fish(SVC)

The standard treatment for columnaris disease in fish is using antibiotics, such as erythromycin or tetracycline, which can be added to the water or given orally.
Formaldehyde-based medications can also be used. Sick fish should be isolated to prevent spreading the disease to healthy fish, and if the disease is severe, euthanasia may be necessary.
It can be treated with environmental improvements such as increasing oxygenation and controlling organic matter.
In addition, copper sulfate (0.5–1.0 ppm) and potassium permanganate (2–3 ppm) can be used in pond treatments, and dip treatments for 1-2 minutes in a 1:2000 copper sulfate solution can be effective.
Oxytetracycline can also be incorporated into fish feed at a rate of 8g/100 kg of fish/day for ten days.
Studies have shown that antibiotics such as chloramphenicol, erythromycin, and oxytetracycline are effective against columnaris disease, while others like colistin, sulfamethoxazole, and neomycin have high minimal inhibitory concentration values.

Prevention & Control Measures of Columnaris Disease in Carp Fish(SVC)

Monitoring feed consumption, pond depth, ammonia levels, and stocking events can help anticipate and prevent outbreaks.
Reducing fish density during high water temperatures can also be effective.
Proper control of nitrates, nitrites, and organic load is crucial to prevent F. columnare from adhering.
Regular water monitoring and probiotics are also promising approaches.
Changing 25% of the aquarium water regularly and maintaining a proper diet can help prevent fish from becoming stressed and susceptible to disease.

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Conclusion

Columnaris disease in carp fish requires quick identification and diagnosis, followed by proper prevention steps such as keeping optimum environmental conditions and preventing overcrowding. If an outbreak happens, treatment choices such as drug treatment and environmental changes can aid in disease control.

Columnaris Management in Carp Fish: Disease Symptoms, Management, Prevention, Causes, Control, and Treatment

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