For shrimp farmers, clean water is a mandatory foundation for a healthy shrimp stock to grow well. Conversely, if the pond is polluted, with accumulated waste, bacteria, algae, and slime adhering to the shrimp’s body, it creates ideal conditions for many diseases to break out, including black gill disease in shrimp. To help farmers detect and treat the disease in time and reduce losses for the crop, please refer to the insights from Vemedim below.
Black gill disease in shrimp and signs for recognition
Black gill disease is one of the common diseases in farmed shrimp, characterized by the gills changing color from red or brown to black, accompanied by signs such as shrimp refusing feed, swimming sluggishly, and so on. The disease often appears when water quality is not assured, the pond environment is polluted, or the shrimp are stressed due to nutrition and other biological factors.
To prevent and handle it promptly, farmers need to observe both the shrimp and the water environment:
Signs on the shrimp’s gills and body
- Shrimp gills change from red → light brown → completely black.
- Shrimp swim near the surface, move sluggishly, and lack oxygen.
- Refuse feed, grow slowly, and have reduced resistance.
- In severe cases, necrosis may be observed at the tips of the antennae, flagella, eyestalks, and appendages if fungi are involved.
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Signs when observing the shrimp pond water environment
- Lots of black mud, dense algae, and high levels of toxic gases.
- The pond has a high shrimp density, with little or no aeration, probiotics, or siphoning.
- The shrimp turn black all over the body, which becomes obvious when the disease progresses severely.
Causes of black gill disease in shrimp
Black gill disease in shrimp does not appear randomly; it results from multiple combined causes, with environmental and husbandry factors playing the most important role. When the pond is not kept clean or the shrimp are stressed due to poor nutrition, black gill disease can easily appear. Specifically:
1. Dirty pond conditions
In high-density ponds, if water is not changed regularly, aeration is insufficient, the pond bottom is not treated with probiotics, and siphoning is not done frequently, organic waste will accumulate. Leftover feed, algal remains, and shrimp feces create a thick sludge layer at the bottom of the pond, which sticks to the shrimp gills and causes them to change from brown to black, leading to black gill disease.
In addition, toxic gases such as NH₃ and NO₂, if accumulated beyond the threshold, will weaken shrimp and may even cause mass mortality.
2. Pond with many toxic algae and slime
When the pond develops a lot of algae, slime, or fouling organisms such as filamentous bacteria, fungi, and protozoa, dirt will easily adhere to the shrimp gills.
3. Heavy metal concentration in the water
Metals such as aluminum and iron in pond water, when combined with an acidic environment (low pH), will deposit on the shrimp gills, causing black coloration and becoming one of the chemical causes of black gill disease in shrimp.
4. Bacterial and fungal infection
Shrimp gills may turn black due to the appearance of melanin pigment when shrimp are infected with bacteria, usually Vibrio, or the fungus Fusarium.
5. External parasite infection
Recent studies show that a parasitic amoeba, Paramoeba sp., can cause black gill disease in whiteleg shrimp, especially when the environment is stressed (high temperature, high salinity, dense stocking).
6. Nutritional deficiency
Shrimp raised in environments lacking algae or vitamin C may also develop black spots on their bodies. Nutritional deficiency reduces resistance, making shrimp more susceptible to black gill disease.
How to treat and prevent black gill disease in shrimp
Before black gill disease causes serious consequences for shrimp and the pond, early recognition and the application of combined treatment and prevention measures are important steps to help shrimp recover and limit economic losses.
Treatment when shrimp have black gill disease
- Disinfect the water with Sodium percarbonate (5 ppm) for the pond bottom and Vemedim BKC 80% in the water, or repeat every 3–4 days.
- Before treatment, supplement Vitamin C and minerals with Anti Shock to increase resistance.
- After disinfection, add probiotics Vemedim Aqua Bacillus to improve the water and pond bottom.
- Change 20–30% of the water daily, and feed shrimp with added vitamins, beta-glucan, and probiotics.
- Remove diseased shrimp, change the water, and clean the pond. The treatment success rate is only about 30%.
- If caused by protozoa, use potassium permanganate, copper sulfate, or formalin according to technical guidance, avoiding overuse.
- Add antibiotics or probiotics to boost resistance if the disease is caused by bacteria, while limiting organic feed and treating slime algae.
- Raise pH with lime (20 kg/1000 m³), and use sodium thiosulfate to absorb metals.
Prevention of black gill disease in shrimp
- Thoroughly clean the pond before stocking shrimp, and install a siphoning pit regularly.
- Filter and treat the water before filling the pond.
- Do not stock too densely, control algae, and increase aeration.
- Avoid excess feed, and periodically use probiotics to treat the pond bottom and water.
- Specialized probiotics for muddy bottoms and Microbe-Lift AQUA C for water can be used to increase resistance and improve shrimp quality.
Thus, managing clean pond water and controlling the environment well is the first “shield” against black gill disease in shrimp and many other diseases. When the water is clean, oxygen is sufficient, and the pond bottom is properly treated, shrimp will be healthier and more resistant to pathogens. With scientific solutions and the support of Vemedim, farmers can feel more at ease and aim for a successful, sustainable shrimp crop. Contact us now if you need consultation or support!
