Dropsy isn't a disease itself - it's a symptom of advanced bacterial infection or kidney failure. The fish's abdomen swells with fluid, scales lift outward giving the classic 'pinecone' appearance. By the time you see pinecone scales, mortality is 60-80% even with aggressive treatment.
Move to hospital tank immediately. Dose Kanaplex (kanamycin) + Metroplex (metronidazole) together for 10-14 days. Add aquarium salt at 1 tbsp per gallon - reduces fluid retention. 25% daily water changes during treatment. Feed medicated food if available.
Same protocol: Kanaplex + Metroplex in hospital tank for 10-14 days. Lower salinity slightly (1.022) reduces osmotic stress. Add Beta-glucan to support immune function.
Dropsy is almost always preventable through husbandry: stable parameters, low nitrates (<20 ppm), quarantine new fish 4-6 weeks, balanced diet with vitamins, avoid stress (overstocking, aggression, parameter swings). Most dropsy cases trace back to chronic stress + suppressed immune system + opportunistic bacteria.
Estimated cost: $40-70.
Sometimes, if caught early (before pronounced pinecone scales). Mortality is 60-80% even with aggressive treatment because dropsy indicates advanced organ damage. Early intervention before scale lifting raises survival to ~50%.
The underlying bacterial cause can spread, but dropsy itself often results from individual immune compromise. Quarantine the affected fish + monitor tank mates closely.
The single most important disease-prevention step: a 4-6 week quarantine of every new fish before adding to your display. See the complete quarantine protocol.