(1) Symptoms:
The affected koi exhibit congestion around the eyes, gill covers, mouth, and at the base of all fins.
(2) Prevention and Control Methods:
During the peak season of fish diseases, apply bleaching powder at a concentration of 1×10⁻⁶ mg/L throughout the pond once every 15 days as a preventive measure, which can be effective.
(3) Treatment Methods:
Bathe the fish in an erythromycin solution at a concentration of 10×10⁻⁶ mg/L for 50–60 minutes, then administer nitrofurazone throughout the pond at a concentration of (0.5–1.0)×10⁻⁶ mg/L. Repeat the treatment with the same concentration after 10 days.
