Health

See also:

Diagnostic Guide to Identifying Disease among Goldfish - Common and not so common ailments, plus problems caused by incorrect water chemistry.
Diseases and Medication of Angelfish - List of common ailments and recommended treatments.
Dr. Jungle's Animal World: Freshwater Fish Disease and Treatment - Index of various disorders, symptom and diagnostics chart, and recommended treatments.
Fish Diseases FAQ - Prevention, diagnosis, and treatment of common ailments.
Fish-Med - Details on fish disease, with photos, prevention tips, and treatment.
Government of Western Australia: Diseases of Farmed Goldfish and Koi - Offers an overview of internal parasite infestation, as well as gill and skin diseases. Includes photos.
Happy Goldfish - A list of common illnesses and diseases. Explains causes, symptoms, treatment and prevention.
National Fish Pharmaceuticals: Aquatic Disease Control Center - Includes a question and answer guide to diagnosis of disease, advanced diseases details, and a Koi pond section.
NetPets: Common Diseases Found in Fishes - Checklist, primary symptoms, afflictions and remedies.
Osmoregulation - Article on osmosis and osmotic stress, fish anatomy and general aquarium terms.
The Sick Fish Page - Diagrams of common goldfish illnesses, and treatment suggestions.