Koi health guide
Koi Health Guide
A practical starting guide for reading koi health: behavior, appetite, body condition, water quality, quarantine, stress, and when to ask for experienced help.
What Healthy Koi Usually Show
Healthy koi are alert, balanced in the water, interested in food when conditions are right, and free from obvious wounds, fin damage, labored breathing, or isolation.
Behavior
Watch swimming, schooling, appetite, flashing, surface behavior, and whether one fish separates from the group.
Body Condition
Check skin, fins, eyes, gills, belly shape, wounds, swelling, posture, and color changes.
Environment
Review ammonia, nitrite, oxygen, pH, KH, temperature, recent additions, treatments, and filter changes.
When To Get Help
Seek qualified help quickly if koi are gasping, rolling, bleeding, developing open wounds, dying, or if several fish decline at the same time.
KoiTalk health pages are educational. They do not replace diagnosis from a qualified aquatic veterinarian or experienced koi professional.
Related Health Topics
Use this guide as the starting point before reading more specific health pages.