What are the symptoms of Dropsy?

A visibly swollen belly, with the fish looking inflated when viewed from above; Scales standing out from the body like a pinecone - the classic sign; Bulging eyes and possible pale swelling around the gill covers and fin bases; Hanging tail-down, sinking, refusing food and losing balance - by this stage recovery is rare. It usually starts with: Long-term poor water quality or temperature swings wearing down the immune system; Fluid imbalance after kidney or liver damage, usually linked to a bacterial infection; Feeding mouldy or rancid, oxidised food; Overcrowding and chronic stress.

How do you treat Dropsy?

In order: 1. Isolate immediately (Move the fish into its own hospital tank with a lower water level and gentle flow so it does not have to fight the current. Dropsy is not directly contagious, but its causes - water and food - affect the whole tank.) 2. Do a thorough water change and fast the fish (Change 30-50% of the water with matched temperature and clean the bottom, fast the fish for 24-48 hours, and test ammonia, nitrite and nitrate to remove every environmental stressor first.) 3. Epsom salt bath (In the hospital tank use Epsom salt at roughly 1-2 g/L for 5-7 days to help draw fluid out osmotically, watching the fish throughout. Epsom salt is not table salt, and it should not be used in a display tank with shrimp, snails or plants.) 4. Antibiotics only if a bacterial infection is confirmed (Only use an antibacterial at the label dose in the hospital tank if there are also signs of infection such as ulcers or red streaks. Dropsy from organ failure alone does not respond to drugs, and extra medication only adds burden.) 5. Give it a week (Observe for 5-7 days: scales flattening and the belly shrinking mean it is working. If the swelling and tail-down posture continue, the prognosis is poor - consider euthanasia rather than letting it waste away.)

What medication treats Dropsy?

Epsom salt (magnesium sulfate): Hospital tank bath at 1-2 g/L for 5-7 days, watching the fish. This is magnesium sulfate rather than table salt and cannot replace a salt bath; it affects plants and invertebrates, so keep it out of the display tank.; Antibiotics (oxytetracycline and similar): Only when a bacterial infection is confirmed, and only in the hospital tank at the label dose for a full course. Dropsy is usually a late-stage syndrome that drugs cannot reverse, so do not keep switching products.

G-04 / 08Freshwater

Dropsy腹水病

Very urgent with a poor prognosis. Once scales stand out it usually marks advanced organ damage, so the sooner the fish is isolated and water is corrected, the better the slim chance of recovery.

Illustration to come

G-04 / 08 · Dropsy

SpecificationsDisease atlas

Cause: Bacteria
Severity: Severe
Contagion: Low contagion
Corals / inverts: Not safe
Also known as: Pinecone disease、Ascites

Symptoms

A visibly swollen belly, with the fish looking inflated when viewed from above
Scales standing out from the body like a pinecone - the classic sign
Bulging eyes and possible pale swelling around the gill covers and fin bases
Hanging tail-down, sinking, refusing food and losing balance - by this stage recovery is rare

Typical triggers

— Long-term poor water quality or temperature swings wearing down the immune system
— Fluid imbalance after kidney or liver damage, usually linked to a bacterial infection
— Feeding mouldy or rancid, oxidised food
— Overcrowding and chronic stress

Treatment, in order

1 · IsolateIsolate immediatelyMove the fish into its own hospital tank with a lower water level and gentle flow so it does not have to fight the current. Dropsy is not directly contagious, but its causes - water and food - affect the whole tank.
2 · Water changeDo a thorough water change and fast the fishChange 30-50% of the water with matched temperature and clean the bottom, fast the fish for 24-48 hours, and test ammonia, nitrite and nitrate to remove every environmental stressor first.
3 · SaltEpsom salt bathIn the hospital tank use Epsom salt at roughly 1-2 g/L for 5-7 days to help draw fluid out osmotically, watching the fish throughout. Epsom salt is not table salt, and it should not be used in a display tank with shrimp, snails or plants.
4 · MedicationAntibiotics only if a bacterial infection is confirmedOnly use an antibacterial at the label dose in the hospital tank if there are also signs of infection such as ulcers or red streaks. Dropsy from organ failure alone does not respond to drugs, and extra medication only adds burden.
5 · ObserveGive it a weekObserve for 5-7 days: scales flattening and the belly shrinking mean it is working. If the swelling and tail-down posture continue, the prognosis is poor - consider euthanasia rather than letting it waste away.

The standard treatment uses copper or formalin, which is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period above before returning the fish.

Medications and cautions

Epsom salt (magnesium sulfate): Hospital tank bath at 1-2 g/L for 5-7 days, watching the fish. This is magnesium sulfate rather than table salt and cannot replace a salt bath; it affects plants and invertebrates, so keep it out of the display tank.
Antibiotics (oxytetracycline and similar): Only when a bacterial infection is confirmed, and only in the hospital tank at the label dose for a full course. Dropsy is usually a late-stage syndrome that drugs cannot reverse, so do not keep switching products.

Prevention

Keep ammonia and nitrite undetectable and avoid prolonged water quality decline
Store food cold and throw away anything mouldy or clumped
Avoid sharp temperature changes and long-term overcrowding
Quarantine new fish before adding them to reduce pathogen introduction

Frequently asked questions

What are the symptoms of Dropsy?: A visibly swollen belly, with the fish looking inflated when viewed from above; Scales standing out from the body like a pinecone - the classic sign; Bulging eyes and possible pale swelling around the gill covers and fin bases; Hanging tail-down, sinking, refusing food and losing balance - by this stage recovery is rare. It usually starts with: Long-term poor water quality or temperature swings wearing down the immune system; Fluid imbalance after kidney or liver damage, usually linked to a bacterial infection; Feeding mouldy or rancid, oxidised food; Overcrowding and chronic stress.
How do you treat Dropsy?: In order: 1. Isolate immediately (Move the fish into its own hospital tank with a lower water level and gentle flow so it does not have to fight the current. Dropsy is not directly contagious, but its causes - water and food - affect the whole tank.) 2. Do a thorough water change and fast the fish (Change 30-50% of the water with matched temperature and clean the bottom, fast the fish for 24-48 hours, and test ammonia, nitrite and nitrate to remove every environmental stressor first.) 3. Epsom salt bath (In the hospital tank use Epsom salt at roughly 1-2 g/L for 5-7 days to help draw fluid out osmotically, watching the fish throughout. Epsom salt is not table salt, and it should not be used in a display tank with shrimp, snails or plants.) 4. Antibiotics only if a bacterial infection is confirmed (Only use an antibacterial at the label dose in the hospital tank if there are also signs of infection such as ulcers or red streaks. Dropsy from organ failure alone does not respond to drugs, and extra medication only adds burden.) 5. Give it a week (Observe for 5-7 days: scales flattening and the belly shrinking mean it is working. If the swelling and tail-down posture continue, the prognosis is poor - consider euthanasia rather than letting it waste away.)
Is Dropsy contagious, and how urgent is it?: Contagion: low contagion. Severity: severe. Cause: bacteria. Very urgent with a poor prognosis. Once scales stand out it usually marks advanced organ damage, so the sooner the fish is isolated and water is corrected, the better the slim chance of recovery.
What medication treats Dropsy?: Epsom salt (magnesium sulfate): Hospital tank bath at 1-2 g/L for 5-7 days, watching the fish. This is magnesium sulfate rather than table salt and cannot replace a salt bath; it affects plants and invertebrates, so keep it out of the display tank.; Antibiotics (oxytetracycline and similar): Only when a bacterial infection is confirmed, and only in the hospital tank at the label dose for a full course. Dropsy is usually a late-stage syndrome that drugs cannot reverse, so do not keep switching products.
Is the treatment for Dropsy safe for corals and inverts?: No. The standard treatment (copper or formalin based) is lethal to corals, shrimp, snails and everything on live rock. Treat in a quarantine tank only, and leave the display tank fallow for the full period given above.