Goldfish Furunculosis is a contagious bacterial goldfish illness. The bacterial infection occurs under the scales.
Symptoms: Raised bumps that appear under the scales. With time these bumps will rupture and an ulcerated area will appear in its place.
Treatment: There is NO known treatment for the ulcers, but some fish do survive. For optimal survival levels increase water temperature to 80 degrees. Furunculosis is a cold temperature bacteria and will not survive in warmer temperatures. Surviving fish will frequently have scars where the ulcers where.
It may be prudent to treat with a broad spectrum antibiotic to decrease chances of secondary bacterial infection in ulcerated areas.