Treatment Protocol for Hydra (Freshwater Polyps)
Fenbendazole (same as planaria) at 0.1g per 10 gallons — kills hydra within 3 days. WARNING: lethal to snails. No-Planaria also effective against hydra. Some aquarists use hydrogen peroxide spot-treatment (syringe directly onto hydra). Three-spot gouramis eat hydra naturally.
How to Identify This Condition
Look for these symptoms in your fish:
- Tiny tentacled organisms on glass/plants
- Green or white tube-like polyps
- Baby shrimp and fry disappearing
- Polyps retract when touched
Early detection is critical — the sooner you begin treatment, the better the prognosis. Observe your fish daily during routine feeding for any behavioral or physical changes.
Root Causes
Understanding what caused the problem helps you prevent recurrence:
- Introduced on plants or live food
- Overfeeding fuels population growth
- Presence of small organisms they feed on
Recommended Medications
The following medications are effective against Hydra (Freshwater Polyps):
- Fenbendazole — follow manufacturer dosing instructions. Treat in a hospital/quarantine tank when possible to avoid disrupting your main tank's biological filtration.
- No-Planaria — follow manufacturer dosing instructions. Treat in a hospital/quarantine tank when possible to avoid disrupting your main tank's biological filtration.
- Hydrogen peroxide (spot treatment) — follow manufacturer dosing instructions. Treat in a hospital/quarantine tank when possible to avoid disrupting your main tank's biological filtration.
Always have these medications on hand before you need them. See our quarantine tank guide for proper treatment setup.
Water Quality During Treatment
Maintain pristine water conditions during treatment. Perform 25% daily water changes using Seachem Prime as your water conditioner. Remove activated carbon from your filter during medication (carbon absorbs medications). Increase aeration with an air stone — sick fish need extra oxygen. Monitor ammonia and nitrite daily with your test kit.
Recovery & Quarantine
This is generally a mild condition. Most cases resolve within 1-2 weeks with proper treatment. Continue monitoring after symptoms clear.
Prevention
The best treatment is prevention. Follow these practices to reduce the risk:
- Quarantine and dip new plants
- Don't overfeed
- Avoid introducing live food from outdoor sources
- Keep three-spot gouramis as biological control
For a complete prevention strategy, read our quarantine tank guide and maintenance schedule.