Dropsy in Fish: Complete Treatment Guide

**Quick Answer:** Dropsy in fish is characterized by a swollen belly and pinecone-like scales caused by bacterial infection and fluid buildup. Treatment includes isolating the affected fish, adding Epsom salt (1 tablespoon per 19 litres), and using antibiotics like API Erythromycin or Seachem KanaPlex. Early intervention is crucial as advanced dropsy has a low recovery rate, with treatment typically lasting 10-14 days.

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What is Dropsy?

Dropsy is not a disease itself but a symptom of severe internal problems in fish. It occurs when fluid builds up inside the fish's body cavity or tissues, causing bloating and the characteristic pinecone appearance as scales protrude outward. This condition is typically caused by bacterial infections, particularly Aeromonas bacteria, that affect the kidneys and liver.

The term "dropsy" comes from an old word for edema (fluid retention). While it can affect any fish species, it's commonly seen in bettas, goldfish, and other popular aquarium fish. Dropsy indicates that internal organs are failing, which is why early detection and treatment are critical for any chance of recovery.

Symptoms

Swollen, distended belly or abdomen

Scales sticking out like a pinecone (the definitive sign)

Bulging eyes (exophthalmia)

Pale gills

Clamped fins held close to the body

Curved spine in severe cases

Lethargy and reduced activity

Loss of appetite

Hiding behaviour

Redness or inflammation of the skin, fins, or vent

Pale or discoloured feces

Causes

Bacterial infections (primarily Aeromonas bacteria)

Poor water quality with high ammonia or nitrite levels

Sudden temperature changes

Weakened immune system from stress or poor nutrition

Parasitic infections that damage internal organs

Liver or kidney damage

Viral infections (less common)

Internal injuries or tumors

Treatment Steps

1. **Isolate the affected fish** - Move to a hospital tank with clean, conditioned water

2. **Test water parameters** - Ensure ammonia and nitrite are 0ppm, nitrate under 20ppm

3. **Add Epsom salt** - Dissolve 1 tablespoon per 19 litres to help reduce swelling (available at Chemist Warehouse for $3-5)

4. **Raise water temperature** - Gradually increase to 26-28°C to boost immune function

5. **Add antibiotics** - Use API Erythromycin ($18-25 at Aquarium Spare Parts Adelaide) or Seachem KanaPlex ($28-35 at specialist stores) following package instructions

6. **Perform daily water changes** - Change 25% of water before each dose of medication

7. **Offer easily digestible foods** - Try frozen daphnia, brine shrimp, or medicated foods if the fish is still eating

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Prevention

Maintain excellent water quality with 0ppm ammonia and nitrite

Perform regular 25-30% weekly water changes

Test water parameters frequently with a reliable test kit

Quarantine new fish for 3-4 weeks before adding to main tank

Disinfect nets, siphons, and other equipment between tanks

Feed a varied, high-quality diet to boost immune function

Avoid overcrowding your aquarium

Maintain stable water temperature and parameters

When to Worry

Dropsy itself is already a serious condition that indicates internal organ problems. If your fish shows the classic pinecone appearance, immediate action is required. The prognosis becomes very poor once the pineconing is severe and widespread across the body. If after 5-7 days of treatment there's no improvement, or if the fish is clearly suffering (unable to swim, gasping, refusing food for several days), humane euthanasia may need to be considered. In Adelaide's climate, particularly during summer when temperatures fluctuate, be extra vigilant about water quality to prevent stress that can lead to dropsy.

Common Questions

**Can a fish recover from dropsy?**

Recovery is possible if caught very early, but the success rate is low once pineconing is evident across the entire body. Early-stage dropsy with minimal pineconing has a better prognosis with aggressive treatment.

**Is dropsy contagious to other fish?**

The bacterial infection that causes dropsy can potentially spread to other fish, especially those with weakened immune systems. Always isolate affected fish immediately.

**How long does it take for dropsy to kill a fish?**

Without treatment, severe dropsy can be fatal within a few days to a week. With treatment, a fish may survive longer, but recovery depends on the severity and how early treatment begins.

**What's the difference between dropsy and normal bloating?**

Normal bloating or constipation doesn't cause the scales to stick out in a pinecone pattern. A bloated fish may have a swollen belly, but the scales remain flat against the body.

**Can I prevent dropsy from recurring?**

If your fish recovers from dropsy, maintain pristine water conditions, provide an excellent diet, and minimize stress to prevent recurrence. However, fish that have survived dropsy may have permanent internal damage that makes them more susceptible to future problems.

Still unsure if your fish has dropsy? Join over 750 Australian aquarists who've used FinsDoc for accurate diagnosis. Upload a photo now at https://finsdoc.com.au and receive expert advice on whether your fish can be treated or if the condition has progressed too far.