The Exact Koi Quarantine Protocol I Use: A Proven 14-Day System for Healthy, Parasite-Free Fish
Quarantining new koi is the single most important step in preventing parasites, bacterial infections, and full-pond disease outbreaks. Part of our complete Koi Diseases & Treatment Guide.
As a 30-year aquaculturist who has handled thousands of fish—from domestic stock to high-end Japanese imports—this is the exact, real-world quarantine protocol I use every time new koi arrive.
This is not theory. This is a proven system designed to stabilize fish, eliminate parasites, and prevent problems before they ever reach your pond.
Why Proper Quarantine Matters
Most koi arrive stressed, immunocompromised, and carrying some level of parasites or bacteria—even when purchased from reputable breeders.
A proper quarantine protocol gives fish time to:
Recover from transport stress
Shed parasites
Stabilize immune function
Reveal hidden health issues
Poor or rushed quarantine is the leading cause of:
Fluke infestations
Anchor worm and fish lice outbreaks
Ulcers and bacterial infections
Sudden spring parasite blooms
Massive losses after new fish introductions
Skipping quarantine does not save time. It creates preventable problems.
Quarantine System Requirements
This protocol assumes:
A dedicated quarantine system
Independent filtration and aeration
Accurate salt measurement
No shared equipment with the main pond
Never share nets, hoses, or tools between quarantine and your pond.
The Proven 14-Day Quarantine Protocol
This is the exact sequence I follow, every time.
Days 1–2: Arrival and Salt Stabilization (5 ppt)
When fish arrive, they are immediately placed into quarantine and salinity is raised to 5 ppt
(5 pounds of salt per 100 gallons).
This step:
Reduces osmotic stress
Stabilizes electrolyte balance
Suppresses early parasite activity
Supports slime coat repair
Fish remain at 5 ppt for a full 48 hours with no other treatments added.
This stabilization window is critical. It allows the immune system to reset before medications are introduced.
Day 3: Reduce Salt and Treat With Purple Magic
After 48 hours, a water exchange is performed to reduce salinity to 1 ppt or less.
Once salt is lowered, a full treatment of Purple Magic is applied.
At this stage, Purple Magic:
Controls surface bacterial load
Cleans and oxidizes damaged tissue
Helps prevent early ulcer development
Reduces microbial pressure during transition
This step creates a clean slate before parasite-specific treatments begin.
Days 4–6: First Prazi Power Treatment (Flukes)
Flukes are the most common parasite found on new koi. Assume they are present unless proven otherwise.
On Day 4:
Prazi Power is dosed at 1.5 g per 100 gallons
No water changes are performed
Treatment remains in the system for three full days
This first cycle eliminates:
Adult flukes
Most juvenile stages
Day 7: Full Flush and Anchor Armor Treatment
On Day 7:
The quarantine system is fully flushed
Refilled with clean, dechlorinated water
Anchor Armor is immediately applied
Anchor Armor targets parasites Prazi does not, including:
Anchor worm
Fish lice
Other crustacean parasites
Anchor Armor remains in the system for three days.
This Prazi → Anchor Armor sequence provides full-spectrum external parasite coverage.
Day 10: Second Prazi Power Treatment (Highly Recommended)
This step is technically optional, but strongly recommended for:
Japanese imports
High-value koi
Any fish with unknown history
On Day 10:
A second Prazi Power treatment is applied at 1.5 g per 100 gallons
Treatment remains for three additional days
Why this matters:
Fluke eggs survive chemical treatment
A second round eliminates hatch-outs
This step dramatically reduces post-introduction fluke outbreaks
Skipping this is one of the most common reasons flukes appear weeks after new fish are added.
Days 11–13: Observation and Behavior Monitoring
After treatments are complete, the fish enter a monitoring phase.
Watch closely for:
Flashing
Gasping at the surface
Clamped fins
Lethargy
Loss of appetite
Isolation from the group
By this stage, fish should be:
Eating aggressively
Active and stable
Showing normal behavior
Any issues that appear now must be addressed before pond introduction.
Day 14: Acclimation and Pond Introduction
If fish remain healthy and stable through Day 14, they are ready for transfer.
A koi that completes this process enters the pond:
Parasite-free
Stabilized
Eating well
Adjusted to captive conditions
No longer transport-stressed
This is how ponds stay healthy long-term.
Final Notes
Quarantine is not paranoia.
It is risk management.
Every experienced koi keeper learns this lesson eventually—either through discipline or through loss. This protocol eliminates guesswork and dramatically reduces preventable disease.
