I. Isolate Sick Fish and Disinfect the Environment
Upon discovering a sick betta, immediately transfer it to a separate treatment tank. The original tank and all equipment must be thoroughly disinfected:
Do not use boiling water for plastic tanks; instead, soak items in a potassium permanganate solution, then rinse thoroughly.
For the treatment tank, use aged tap water (water left to sit and dechlorinate) or purified water. Maintain the water temperature at 26–28°C (1–2°C higher than the original tank).
II. Medication Treatment Plans
1. Salt Bath
Add 3–5 grams of sea salt per liter of water (0.3%–0.5% concentration). This regulates osmotic pressure and inhibits bacterial growth.
2. Antibiotic Baths
Yellow Powder (Nitrofurazone): Use 15 mg per liter of water. Keep the tank away from light. Replace 30% of the water daily and replenish the medication; continue treatment for 7 consecutive days.
Oxytetracycline: Option 1 – 2 mg per liter of water. Option 2 – 0.5 grams for a 100-liter tank (full-tank treatment).
3. Severe Infections
Soak the fish in a potassium permanganate solution (1 gram per 50 liters of water) for 20 minutes.
Or, apply povidone-iodine as a full-tank treatment (0.5–1 mg per liter of water).
III. Water Quality Management and Auxiliary Treatment
1. Water Change Frequency
Replace 1/3 of the tank water weekly. Maintain a pH level of 6.5–7.5, and use nitrifying bacteria to stabilize water quality.
2. Aeration and Light Avoidance
Provide continuous aeration during treatment and keep the tank away from direct light.
3. Nutritional Support
Feed high-protein live food (e.g., disinfected brine shrimp).
Add vitamin B2 or allicin to the feed to boost the fish’s immune system.
IV. Prevention Measures
Disinfect the tank regularly (monthly) using quicklime or bleach.
Avoid mixed-species tank setups or sharp tank decorations to reduce the risk of fish scraping injuries.
Keep water clean; when changing water, ensure minimal temperature fluctuation and stable pH levels.
V. Important Notes
Fin rot is often caused by poor water quality – prioritize water improvement before using medication.
Do not use carcinogenic medications such as malachite green.
If the condition does not improve, try using almond leaf extract to aid in fin repair.