Koi Quarantine: The Complete Hub for Dealers, Breeders, and Serious Collectors

By KoiQuanta Editorial Team|Updated Mar 2026

Up to 90% of disease introductions to koi collections happen in the first 30 days after a new fish arrives. Quarantine isn't supplementary - it's the most important disease prevention practice in koi keeping, and for dealers it's a legal and commercial necessity.

This hub covers everything: the protocols, the setup, the treatments, the record-keeping, and the standards that separate operations that lose fish to preventable disease from those that don't.

TL;DR

At 65-68°F, you get a meaningful KHV observation window.
Below 55°F, you don't - KHV won't express at cold temperatures.
Start praziquantel dose 1 at 2.5-5 ppm on days 5-7.
Never stop an antibiotic course early because the fish "looks better" 2.
Never combine potassium permanganate with formalin 3.
Always have maximum aeration during formalin treatment 4.
Always build salt up slowly - never add full dose at once 5.

What Quarantine Actually Is

Quarantine isn't just holding fish in a separate tank for a few weeks. Professional quarantine is:

A controlled observation window long enough to detect disease expression
A treatment protocol that addresses known disease risks prophylactically
A documentation system that records what you observed, what you did, and when
A discharge criteria framework that defines exactly when fish are safe to move

Without all four elements, it's just a temporary holding tank - and that's not the same thing.

The Core Protocols

How Long to Quarantine

Domestic fish, reputable source: 21 days minimum
Japanese imports, show fish, unknown sources: 42 days minimum
Outbreak situation or post-disease treatment: Restart clock, extend as needed

The temperature matters as much as the duration. At 65-68°F, you get a meaningful KHV observation window. Below 55°F, you don't - KHV won't express at cold temperatures. Heat your quarantine tanks year-round.

Full guide: How Long to Quarantine Koi

Standard 21-42 Day Protocol

Days 1-3: Observation only. No treatment. Establish behavioral baseline. Record twice daily.

Days 4-7: Begin salt at 0.1%, build to 0.3% over 48 hours. Start praziquantel dose 1 at 2.5-5 ppm on days 5-7.

Days 8-14: Active monitoring. Watch for parasite signs, behavioral changes, any deaths. Maintain salt at 0.3%.

Days 14-18: Praziquantel dose 2 (catches hatched Dactylogyrus juveniles from post-dose-1 eggs).

Days 15-42: Clearance phase. Daily observations. Discharge criteria approaching.

Full protocol: New Koi Quarantine Protocol

Tank Setup

What You Need

A quarantine tank is fundamentally different from a display pond:

Bare bottom (no substrate - removes parasite refugia and improves observation)
Established filtration, seeded from your main system
Temperature controlled at 65-68°F year-round
Strong aeration
Dedicated equipment (never share nets or buckets with display)

Sizing by Fish

| Fish size | Minimum tank volume (per group) |

|-----------|--------------------------------|

| Tosai (4-8") | 150-250 gallons |

| Nisai (8-16") | 300-500 gallons |

| Jumbo (16"+) | 500-1000+ gallons |

Full guide: Koi Quarantine Tank Setup

Treatment Reference

Prophylactic Treatments for All New Fish

Salt: 0.3% (2.5 lbs per 100 gallons) - osmotic support, mild antiparasitic

Praziquantel: 2.5-5 ppm - flukes (two doses required, 10-14 days apart)

Common Disease Treatments

| Disease | Treatment | Notes |

|---------|-----------|-------|

| Skin/gill flukes | Praziquantel 2.5-5 ppm | Two doses |

| Ich | Salt 0.5% + heat to 78-80°F | Or malachite green/formalin |

| External bacteria/fungi | Potassium permanganate 2-3 ppm | Monitor continuously |

| Bacterial ulcers | Antibiotics + wound care | Full course required |

| Anchor worm/lice | Mechanical removal + organophosphates | Multiple rounds |

The Most Important Treatment Rules

Never stop an antibiotic course early because the fish "looks better"
Never combine potassium permanganate with formalin
Always have maximum aeration during formalin treatment
Always build salt up slowly - never add full dose at once
If KHV is suspected, contact your state veterinarian - don't attempt treatment

Quarantine by Situation

New Arrivals from Japan

Forty-two days at 65-68°F. USDA APHIS compliance documentation. PCR testing at day 14-21 for high-value fish. Two-dose praziquantel protocol. Salt at 0.3%.

Full guide: Japanese Koi Import Quarantine

After Koi Shows

Minimum 28 days. High-risk exposure from mixed-source fish environments. Prophylactic praziquantel plus salt to 0.5%. Consider PCR testing for major shows.

Full guide: Quarantine Koi After Shows

Emergency Quarantine (Sick Fish)

Isolate immediately. Bare container, aeration, temperature match. Assessment before treatment. Salt first. Targeted treatment once diagnosis is clearer.

Full guide: Emergency Koi Quarantine

Parasite Quarantine

Two-dose praziquantel timed around egg hatching window. Salt to 0.3-0.5%. Ich requires different treatment (heat + salt or malachite green/formalin).

Full guide: Parasite Quarantine Protocol

Bacterial Quarantine

Isolate. Correct water quality first. Wound care under anesthetic. Antibiotics for full course (10-14 days minimum). Discharge not until wounds are fully closed and 14 days clean.

Full guide: Bacterial Quarantine Protocol

Disease Reference

KHV (Koi Herpesvirus)

The most serious disease in koi keeping. No treatment. Near-100% mortality in acute outbreaks. Reportable to USDA APHIS. Prevention is the only strategy: quarantine, PCR testing, biosecurity.

Peak expression: 59-77°F. This is why quarantine temperature matters.

Full guide: KHV Koi Herpesvirus Guide

Spring Viremia of Carp (SVC)

Reportable disease. Hemorrhagic septicemia in cold to mid-range temperatures (41-63°F). Rare in US koi populations but present.

Aeromonas / Bacterial Ulcers

Most common bacterial disease. Causes ulcers, fin rot, and in severe cases, systemic infection. Treatable with antibiotics if caught early.

Record-Keeping and Documentation

What to Record

Every quarantine observation should document: date and time, fish count, behavioral status, clinical signs, feeding response, water parameters (temperature, ammonia, nitrite, pH), treatments administered (product, dose, method).

Why Documentation Matters for Dealers

Legal protection if a customer claims disease was present at sale
Source data for buyer documentation (builds customer confidence)
Evidence of professional operation for regulatory inspection
Required documentation for import compliance

Buyer Packs

A professional buyer pack includes: quarantine duration, water parameters summary, treatments administered, discharge criteria met, fish description and photos. KoiQuanta generates this from your daily records automatically.

Dealer Quarantine Standards

Professional koi dealers use 42-day protocols with daily documentation as the industry standard. The dealers who've survived KHV outbreaks all run longer, more rigorous quarantine than the ones who haven't.

Documentation should include: batch arrival records, daily observation logs, treatment logs, and discharge sign-offs.

Full guide: Dealer Quarantine Standards

KoiQuanta: Purpose-Built for This Workflow

KoiQuanta was designed around the reality that quarantine management is operationally complex - and that the difference between good quarantine and great quarantine is systematic prompting, accurate dosing, and documentation that's actually usable when you need it.

The platform:

Generates day-by-day protocols automatically on batch setup
Prompts observations at scheduled times
Calculates treatment doses by tank volume and fish biomass
Tracks discharge criteria against a live checklist
Generates buyer documentation from your quarantine records

For dealers managing multiple quarantine batches simultaneously, KoiQuanta is the difference between running a documented professional operation and hoping you remember which tank got the second praziquantel dose.

No competitor - KoiControl, generic aquaculture apps, or paper systems - manages the quarantine workflow at this level.

FAQ

What is the quarantine protocol for koi dealers?

Professional koi dealers use a minimum 42-day protocol with daily observation documentation, prophylactic salt and praziquantel treatment, daily water parameter logging, and formal discharge criteria. Most serious operations use KoiQuanta or an equivalent digital system to manage multiple batches simultaneously and generate buyer documentation from quarantine records. The protocol includes: arrival documentation, daily observations twice per day, treatment logs, water change records, and discharge sign-off.

How do I know when to end quarantine?

Discharge criteria are: minimum days elapsed (21 for low-risk domestic, 42 for imports/show fish), zero mortality in past 14 days, all fish eating normally, no clinical signs, water parameters stable, all treatment courses completed, and 14 clean observation days post any treatment. KoiQuanta tracks these criteria automatically against your logged data. Every criterion must be met - not most, all.

What does KoiQuanta offer for quarantine management?

KoiQuanta provides day-by-day protocol generation, scheduled observation prompts, treatment dose calculators, discharge criteria tracking, and buyer documentation generation from quarantine records. It supports multiple independent tank profiles, batch tracking, and compliance reporting. For dealers, it turns daily quarantine records into buyer documentation automatically - a capability no competitor offers at this level.

What is Koi Quarantine: The Complete Hub for Dealers, Breeders, and Serious Collectors?

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Sources

Associated Koi Clubs of America (AKCA)
Koi Organisation International (KOI)
University of Florida IFAS Extension Aquaculture Program
Fish Vet Group
Water Quality Association