Dropsy in aquarium fish
PetPort EditorialLast reviewed
Why is my fish swollen with scales sticking out?
A swollen body with scales standing out from it — the classic pinecone look, best seen from above — is dropsy. It is not a disease in itself but a sign of fluid accumulation, usually from organ failure or serious internal infection. The prognosis is poor, and comfort and water quality matter more than aggressive treatment.
General guidance for pet parents, not a diagnosis. Every animal is different — confirm anything that concerns you with your veterinarian.
Quick reference
| Not a disease | A sign of fluid accumulation from an underlying problem |
|---|---|
| Best viewing angle | From directly above — the pinecone is invisible from the side |
| Underlying causes | Kidney or liver failure, internal infection, tumour |
| Prognosis | Poor once scales are raised |
| Not contagious as such | But shared water quality often affects the whole tank |
| Most useful action | Immaculate water and reduced feeding |
What is happening
Dropsy describes fluid building up in the body cavity until the scales are pushed outward. The cause sits underneath it: kidney or liver failure, internal bacterial infection, or a tumour. By the time the pinecone appearance is visible, the underlying disease is usually advanced.
Signs to watch for
- Body swollen, scales standing out — most obvious looking down from above
- Bulging eyes, pale or stringy droppings, and loss of appetite
- Lethargy, sitting on the substrate or hanging at the surface
What you can do
- Move the fish to a clean quarantine tank with pristine, matched water
- Keep the water immaculate — this is supportive care, not a cure
- Stop overfeeding; uneaten food worsens water quality fast in a small tank
See a vet if
As soon as the pinecone appearance is visible, if an aquatic vet is reachable. Where none is, focus on water quality and on preventing further cases, and be prepared to consider humane euthanasia if the fish is clearly suffering.
In India specifically
Small unfiltered bowls remain widely sold in India, particularly for goldfish and bettas, and they are the single most common background to chronic organ disease in pet fish here — water quality in a bowl cannot be maintained. If your fish is in a bowl, moving it to a filtered, appropriately sized tank prevents far more disease than any treatment cures.
Common questions
Can dropsy be cured?
Rarely once the scales are visibly raised, because that stage reflects advanced organ failure. Fish caught very early, with a treatable bacterial cause, sometimes recover with veterinary antibiotic treatment. Be realistic: most cases at the pinecone stage do not survive.
Is dropsy contagious to my other fish?
Dropsy itself is a sign, not a transmissible disease. But if the underlying cause was an infection or poor water quality, the other fish share that exposure. If a second fish develops it, treat the tank conditions as the primary suspect.
Should I euthanise a fish with dropsy?
It is a fair question to ask when the fish has stopped eating, cannot stay upright, or is visibly distressed with no response to treatment. Clove oil is the method most commonly recommended for humane euthanasia of aquarium fish; an aquatic vet or specialist store can advise on doing it correctly.
Does overfeeding cause dropsy?
Not directly, but chronic overfeeding degrades water quality and stresses the liver and kidneys over time, which is the ground dropsy grows from. Uneaten food decaying in the substrate is one of the commonest reasons a home aquarium slowly deteriorates.