White Spot on Black Koi Near Eye: Parasite vs. Disease Triage

Single Spot, Active Fish = Good Sign

12–13K gal, 5" black koi, one white spot near eye, stable 1 week, no spread, eating well. Not classic Ich (multiple, salt-like, spreading).

Differential

• Lymphocystis (viral): White/pink cauliflower nodules. Self-limiting, cosmetic.
• Epitheliocystis (bacterial): White cysts on gills/skin. Rare.
• Trauma/scar: Healed injury.
• Pigment cell cluster: Normal in dark koi.

Action Plan

1. Photo/document weekly.
2. Do not treat pond — risks biofilter, plants, other fish.
3. If spot grows/spreads → net fish, examine in bowl, photo for vet/forum.
4. Salt? Only if confirmed parasite. 0.3% in hospital tank.

Key Question

Do you add pond salt routinely? Chronic low salt (0.1%) suppresses many parasites.