The prevention and treatment of betta fish fungal infections (such as saprolegniasis) require a comprehensive approach that combines understanding of causes, symptoms, and treatment plans. Below is a summary of key information:
I. Common Causes
Water Quality and Temperature
When water temperature drops below 20°C, saprolegnia fungi reproduce rapidly and easily infect fish through wounds on their bodies.
Deteriorating water quality (e.g., accumulated leftover food, insufficient water changes) exacerbates fungal growth.
Fish Body Injuries
Parasite bites, fights, or transportation friction cause skin damage, creating entry points for fungi.
II. Clinical Manifestations
Typical Symptoms: White cotton-like growths (hyphae) appear on the fish's body or fins; in severe cases, a white film covers the entire body.
Abnormal Behaviors: Sick fish show reduced appetite, sluggish swimming, and may rub against tank walls or lie at the bottom.
III. Treatment Plans
Salt Bath and Temperature Increase
Add 3 grams of coarse salt (non-iodized) per liter of water, and gradually raise the temperature to 28-30°C (maximum 2°C increase per day).
Maintain this regimen for 3-5 days, and replace 1/3 of the water with temperature-matched fresh water during water changes.
Medication Treatment
Methylene Blue: Dilute according to product instructions (usually 1-2mg/L) and bathe the fish for 30 minutes daily.
Potassium Permanganate: Give a short 20-minute bath, then isolate the fish for rest.
Avoid Malachite Green: It is highly toxic and can easily kill fish if misused.
Auxiliary Measures
Stop feeding for 2-3 days to reduce water contamination; after recovery, feed high-protein food (e.g., bloodworms).
Isolate sick fish and disinfect the entire tank (using UV lights or salt baths).
IV. Prevention Recommendations
Water Quality Management: Change 1/3 of the water weekly and maintain a stable water temperature (24-28°C).
New Fish Quarantine: Isolate newly purchased fish for 3-5 days to confirm they are disease-free before introducing them to the main tank.
Reduce Stress: Avoid sudden water changes or temperature fluctuations, and provide hiding spots to reduce the risk of fights.