Koi Ulcer Treatment: Betadine, Quarantine, and Pond-Wide Care

Managing a Koi Ulcer: From Quarantine to Pond Treatment

A 14-inch, 3-year-old koi developed a corn-sized, dark pink bulging spot (not open). Owner treated with Betadine swab, then 3 weeks of MelaFix and salt in quarantine. The spot flattened and paled but persisted.

Expert Assessment

• Likely a bacterial ulcer (Pseudomonas/Aeromonas)—common in ponds
• MelaFix/salt helps but may not resolve established ulcers
• Injectable antibiotics (e.g., Baytril) from a koi vet are ideal
• KoiZyme prevents ulcers but doesn't treat existing ones

Quarantine vs. Pond Return

• Quarantine pros: Targeted treatment, lower medication cost
• Quarantine cons: Stress may impede healing
• Pond return pros: Natural environment, treat whole pond with salt/MelaFix/KoiZyme
• Pond return cons: Other fish already exposed; antibiotic treatment cost-prohibitive

Personal recommendation: Return to main pond with salt, MelaFix, and KoiZyme. Monitor all fish.