Confused because koi fish are prone to disease

Along with economic and social development, the hobby of breeding koi carp (koi carp) as an ornamental plant and feng shui is gaining popularity not only in Japan, but also in most countries of the world, including Vietnam. This is a fish that is not only eye-catching in color but also known for its high value and bringing economic efficiency to people.

In Hai Phong, hundreds of households have converted inefficient aquaculture land to koi farming, and all are making “terrible” incomes. However, the development of aquaculture in general still faces some difficulties, especially in disease prevention and control.

As the second largest koi breeding household in Hai Phong, Mr. Vu Van Tang currently has nearly 2 hectares of aquaculture and koi fish farming in My Duc Township, An Lao District. On average, Mr. Tang’s family supplies more than 30,000 juvenile fish and commercial products to the north market (from Nghe An) every year, earning billion dongs.

To have the property and success like today, Mr. Tang also experienced enough bitterness, bitterness, sweetness and meat with koi fish. There was a time when it seemed like he lost his entire career due to the illness.

The story began on the day Mr. Tang went to the wild lagoon area on the banks of the Van Uc River in the area of ​​My Duc Township, An Lao District, Hai Phong City to start a business. Borrow enough sugar and accumulated capital to get VND 600 million, then burn it all into koi fish.

After the first crop was swept away by floods, Mr. Tang renovated his pond, but just then the disaster continued to stabilize. It was 2014, after being stocked with fish for a while, Mr. Tang made friends. He donated 1 Chinese koi fish, very nice yellow color for breeding. Thought to catch gold but unexpectedly this koi fish took away 1/3 of his family’s wealth by directly seeding pathogens and killing most of the koi fish in the pond.

“At that time, due to lack of experience and knowledge, the brothers gave a Chinese koi fish for breeding, the yellow fish was very beautiful, I did not isolate subjectively, then the lice were parasitic on this fish. cause disease and spread.” the pond. Even though I took a salt bath, I still died later when I found out almost all the fish were affected, all were thin. I almost lost my job back then,” Tang recalls sadly.

Beware of spring and the rainy season

After Mr. Tang found success and made money from koi fish, he expressed his desire to share his practical knowledge with those interested in farming, especially aquaculture and koi fish. Smiling, Mr. Tang shared that basically, like other common fish, koi fish are easy to breed, but they are also prone to diseases when kept in unsanitary and polluted water environment.

Common diseases in koi fish such as body ulcers, scale loss, white spots, sore lips, ulcers, skin worms… The main cause of the disease is not regular cleaning and renovation of the koi pond, resulting in polluted water sources. In addition, disease transmission to old fish occurs because of the failure to deal with microorganisms and organisms from the start when fish are not released, or new fish are not isolated when purchased.

In addition, koi food is of unknown origin, expired, or was not processed prior to feeding the fish, or the water filtration system in the outdoor or indoor aquarium is substandard, or the filter is not powerful enough. Compared to the volume of the lake, the irregular change in pH, temperature in the lake… is also the cause of fish diseases.

In order to prevent fish diseases, it is necessary to regularly clean the lake, control the growth of algae and algae in the lake, take timely measures, as well as always pay attention to the pH level in the lake of 7 – 7.5 pH and the aquarium temperature must be kept at a suitable temperature of 30 – 32 degrees Celsius.

During the rearing, it is necessary to regularly monitor the way of life of the koi fish. If the fish shows abnormal signs, such as B. sluggish swimming, slow swimming, not eating, or many abnormal spots on the body, immediately isolate the fish. to monitor and interrogate fish diseases to take early action to avoid infecting the entire flock.

From practical experience, Mr. Tang said that in order for koi fish to grow up quickly and be healthy, they must first select good varieties, bad and weak varieties, no matter how carefully you take care of them, they cannot develop satisfactorily. This determines 50% of the health and growth of the fish.

“I raised for many years and learned from experience that koi fish often get sick in the spring. When the weather is cold, they often get seriously ill, which is very difficult to treat. Second, a change in ambient temperature (sunshine and rain), especially in sudden rain and long-term rain, leads to dilution of the microorganisms in the tank. If the diet is not appropriate, it can lead to disease. The value of koi fish is great, so a lot of money is often invested in it, from food to accompanying breeding equipment. Therefore, when the fish dies, the damage is never small,” said Vu Van Tang.

Mr. Tang pointed out that novice koi breeders should pay attention to choosing fish with a balanced shape, no abnormalities, no scratches, bright colors, healthy, buoyant and quick to respond. After purchase, the fish need to be raised in a different tank to practice adjusting to the new environment and help the fish get rid of pathogens.

In addition, farmers should also note that newly purchased koi fish need to prepare additional tanks with oxygen filtration and aeration systems mixed with about 5 kg of salt. This salt is mixed with 1000 liters of water and 1 g of tetra water, or the fish are bathed with potassium permanganate.

If there are sick fish in old koi fish in the aquarium, it is necessary to clean the water before adding new fish to the aquarium. When the fish in the aquarium are stable, it is best not to add newly purchased fish to the aquarium as this can lead to the emergence and spread of pathogens. If there are sick fish in the aquarium, you should not buy new fish to release without treating the disease or pathogens in the lake.

“One mistake koi aquarists often make is overfeeding their fish, although it’s a lot of fun to create a connection between the player and the fish. These things make the fish more susceptible to diseases, the fish become obese, no longer look slender and flexible, and also cause pollution of the koi aquarium because the food left in the lake is not treated,” Tang shared.

According to the Ministry of Agriculture and Rural Development of An Lao District, this place has an aquaculture area of ​​798 ha, including 40 households raising koi fish, with a total area of ​​16.5 ha (which accounts for about 2%). , including Chien Thang, My Duc, An Thang and Quang Trung communities with very high profits. Koi fish farmed in An Lao are mainly shipped to the city of Hai Phong and some neighboring provinces and cities such as Hanoi and Hung Yen through private traders.