Dropsy
Symptoms
Severe abdominal swelling combined with scales protruding outward like a pinecone — the hallmark sign. Bug-eyed appearance (exophthalmos). Lethargy, loss of appetite, sometimes pale gills. The pinecone scale pattern indicates internal fluid buildup pushing scales away from the body.
Causes
Not a single disease — a symptom complex caused by kidney or organ failure that prevents fluid regulation. Underlying causes include severe bacterial infection (often Aeromonas), Mycobacterium (fish TB), parasites, or chronic poor water quality. By the time scales pinecone, the underlying disease is usually advanced.
Treatment
Poor prognosis at the pinecone stage — survival is uncommon but not impossible. Isolate the fish in a hospital tank with clean water. Aquarium salt at 1 tablespoon per 3 gallons helps reduce edema by drawing fluid out osmotically. Broad-spectrum antibiotics like kanamycin or a Triple Sulfa combination are sometimes attempted, but the kidney damage is often irreversible. If the fish stops eating and develops secondary symptoms, euthanasia (clove oil overdose, blunt force) is the humane choice.
Prevention
Maintain pristine water quality. Quarantine new fish — Mycobacterium is one underlying cause and is contagious. Don't overfeed. Address any bacterial infection early before it reaches organ damage.
Notes
A constipated goldfish or pufferfish that looks bloated but has flat scales is NOT dropsy — that's just constipation, treatable with fasting and shelled peas. True dropsy requires the pinecone scale pattern.