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How to Treat Goldfish Dropsy with Pinecone Scales: Complete Medication Guide

Problem

My goldfish has pinecone scales and a bloated stomach. I tried oxytetracycline (土黄素) baths for several days, but the fish shows no improvement. What medication should I use, and how should I apply it?

Environment

  • Thai lion goldfish (泰狮) with dropsy symptoms
  • Previous treatment: oxytetracycline bath (no improvement)
  • Fish still active and swimming
  • Hospital tank available

What Happened?

I followed some online advice and used oxytetracycline baths. But after several days:

  • Fish produced waste (good sign)
  • But bloating and pinecone scales remained unchanged
  • No visible improvement

I realized I needed a more effective treatment protocol.

How to Solve It?

The community recommended a structured approach with stronger antibiotics. Here’s the protocol I learned:

Treatment Protocol Overview

Dropsy treatment timeline
Day 1-5: Gentamicin immersion + daily water changes
Day 3+: If no improvement → Add topical metronidazole
Day 5-7: Monitor for reduced swelling
Day 7+: If scales return to normal → Gradual recovery

Step-by-Step Treatment

Step 1: Isolate the fish

Use a hospital tank. Treat alone—never in the main tank with other fish.

Step 2: Add salt

Salt bath setup
Hospital tank size: 20L
Salt amount: 60-100g (0.3-0.5% salinity)
Purpose: Reduce fluid retention, ease stress

Step 3: Gentamicin treatment (primary method)

Gentamicin dosage protocol
Medication: Gentamicin (庆大霉素)
Dosage: 2-3ml per 10L water
Preparation strength: 80,000 units
Application: 24-hour immersion
Water change: 50% daily, replace medication
Duration: 5 consecutive days

Example for a 20L tank:

  • Add 4-6ml gentamicin (80,000 units preparation)
  • Leave fish in medicated water for 24 hours
  • Next day: drain 50% water (10L), add fresh water + 2-3ml gentamicin
  • Repeat for 5 days

Step 4: Furazolidone alternative

If gentamicin isn’t available, use furazolidone (呋喃唑酮):

Furazolidone treatment
Medication: Furazolidone (呋喃唑酮)
Application: Add directly to water
Follow package dosage instructions
Duration: 5-7 days with daily water changes

Step 5: Metronidazole for stubborn cases

If bloating persists after 2-3 days of gentamicin:

Topical metronidazole application
Medication: Metronidazole powder (甲硝唑)
Method: Apply to swollen belly area with cotton swab
Warning: External application only—avoid mouth/gills
Start: Day 3 of treatment, if no improvement
Frequency: Once daily

Important: Do NOT continue feeding

The fish should fast during treatment. Feeding adds digestive stress.

The Reason

I think oxytetracycline didn’t work because:

  1. Wrong antibiotic choice — Oxytetracycline may not target the specific bacteria causing the infection
  2. Insufficient dosage — Bath treatments often don’t reach effective concentrations
  3. No water changes — Medication degrades over time; daily replacement keeps concentration stable

Gentamicin is effective because:

  • Targets gram-negative bacteria (common cause of dropsy)
  • Works well in water immersion
  • Reaches internal organs through absorption

Common Mistakes

MistakeConsequenceCorrect Approach
Salt aloneBacteria surviveAdd antibiotics
No water changesMedication loses potencyChange 50% daily
Wrong dosageTreatment ineffectiveFollow exact measurements
Feeding during treatmentDigestive stressFast the fish
Treating in main tankRisk to other fishUse hospital tank

Summary

In this post, I showed how to treat goldfish dropsy with specific medications. The key point is using gentamicin (2-3ml per 10L, 80,000 units) with daily 50% water changes for 5 days, or furazolidone as an alternative. For stubborn cases, apply topical metronidazole starting day 3. Isolate the fish, add salt, and stop feeding during treatment.

Final words

More reading and next steps

That is the main thread of the article. Keep the links below handy, and use the related posts to continue exploring the same topic from a different angle.

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