(1) Symptoms:
The gill filaments appear pink or pale, followed by tissue damage and increased mucus production, often accompanied by sludge. In severe cases, the inner epidermis of the gill cover becomes congested, and the middle section of the epidermis erodes, forming a roughly circular transparent area, commonly known as a "skylight," with the cartilage exposed.
(2) Prevention and Treatment Methods:
-
Bathe the fish in a 2% saline solution for 5–10 minutes at water temperatures below 32°C.
-
Bathe the fish in a nitrofurazone or furazolidone solution at a concentration of 20×10⁻⁶ mg/L for 10–20 minutes.
-
Alternatively, administer nitrofurazone solution at a concentration of 2×10⁻⁶ mg/L throughout the pond, soak for several days, and then replace with fresh water.
