Koi Health - Information on Koi Herpesvirus


The following general husbandry and health guidelines are derived from the Florida Aquaculture Best Management Practices followed by the Best Management Practices for Finfish Aquaculture in Massachusetts. Both are available online (see References).  Not all recommendations will be applicable to all facilities and recommendations are general rather than koi specific. Some requirmens are applicable only to licensed (commercial) aquaculture facilities.

From the Florida Aquaculture Best Management Practices:

“Good aquatic animal health practices are necessary for the success of any aquaculture production facility. Animals are naturally healthy. A sound management and sanitation program will greatly minimize pathogens and disease in your facility. Knowing the health status of aquatic animals, followed by early diagnosis or prevention of disease is critical to successful production. Disease prevention is based on good animal husbandry practices, including the reduction of animal stress, minimization of pathogens in the culture environment, and quarantine of unhealthy animals.”  Aquaculturists are strongly encouraged  to develop a written aquatic animal health management plan for their facility. The following Best Management Practices, when used in consultation with an aquatic animal health professional or state veterinarian office, are intended to provide the basic components of an aquatic health management plan.

Contact your aquatic animal health professional or the State Veterinarian’s Office in the event of any unusual or abnormal occurrences of disease or pests affecting your aquatic species.  

All health records must be retained for at least two years by certified aquaculturists. These records, at a minimum, shall include:

  • Aquaculture Certification Number
    Name and Address of consignor
    Name and Address of consignee
    Date of Shipment
    Date of entry/receipt
    Total number of aquatic animals by species
    Any pertinent recent test results performed to the group of aquatic animals

Follow accepted animal husbandry practices to maintain a favorable growing environment, such as but not limited to, the following:

  • Avoid over crowding
    Maintain proper nutritional programs
    Promptly remove uneaten or undigested food
    Promptly remove dead animals
    Maintain high quality water and oxygen levels
    Minimize stress such as high light intensity, handling, and extreme or rapidly changing temperatures

Aquatic animals affected by an abnormal occurrence of disease and an undetermined disease should be sent to a diagnostic laboratory for analysis.

Use medications and remedial agents consistent with the label instructions or as directed by a licensed veterinarian.

Institute effective biosecurity measures consistent with BHPs found herein.

Educate personnel on the normal behavioral patterns of aquatic species, to easily distinguish abnormal behavior patterns as a means for early recognition of stress or disease.

When necessary, establish adequate quarantine practices and procedures.

Establish a parasite diagnosis and control program.

Institute a daily program of observing fish behavior and feeding activity to detect disease problems.

Periodically test water quality for dissolved oxygen, pH, temperature, ammonia and nitrite, total alkalinity and total hardness. Know the physiological limits of your species. Establish control and response actions when deviating from normal values. Document all corrective actions.

Feed a high quality diet proper for the species you are raising. Store feeds and medications under cool, dry conditions to prevent degradation.

Sanitize nets and fish handling equipment to prevent the spread of disease.

Provide employee education on the importance of facility cleanliness, safety, cleaning and disinfecting for good animal health.

Promptly remove pathogen harboring organic debris from tanks or ponds.

Sanitize tanks or ponds following disease outbreaks or before stocking with new populations.

From the Massachusetts Best Management Practices:

•Fish must be obtained from reputable, experienced, disease-free hatcheries.
• Health inspections and certification of their absence for diseases that are relevant for the cultured species should be obtained. •Fish should be inspected for signs of stress before introducing them to the system.

•Fish should be quarantined and acclimated with water from the new system before introduction into production units.

•Fish should be transported using industry standard stocking densities and water quality parameters for the species cultured.•Fish heath should be monitored visually and fish health experts contacted if questions arise. It is prudent to establish relationships with fish health experts before a disease outbreak to expedite shipment, diagnosis and treatment.

Regarding Aquaculture Chemicals:

•A diagnosis of the problem(s) should be obtained from a licensed pathologist or veterinarian before any treatment.
•Professional advice should be sought if there is any doubt as to when or how to use regulated products.
•Regulated products must be used only for those species and indications listed on the label, unless extra-label use is specifically prescribed by a licensed veterinarian.
•Product labels should be read and directions followed carefully.
•Proper dosage, amount, or concentration for the species, area, and/or specific condition should be used.
•A small portion of the afflicted population should be treated before treating the entire population to ensure efficacy and safety of treatment.
•Use the correct method and route of application or administration, whether by spraying aquatic vegetation, water treatment (ponds, tanks, or immersion), injection, or oral administration (medicated feed and some biologics).
•Treated populations or stocks should be clearly identified.
•Antibiotic drugs or medicated feed for disease prevention should not be used unless they are specifically approved for that use.
•Keep accurate records.
•Environmental impacts of discharging treated water should be mitigated.
•Requirements concerning personal safety measures and proper procedures for farm workers and pesticide applicators that handle or apply regulated products should be followed.
•Economic consequences, both short- and long-term, of treatment should be considered before using a regulated product (Sometimes the best approach is to let the disease run its course).
•Water quality should be monitored and maintained.

Regarding Feed Management:

  •  Feed should be purchased from a reputable manufacturer.
  •  Only fresh, high quality feed should be used.
  •  Nutritional requirements for particular species should be identified and proper feed should be used accordingly.
  • Quality feed should be purchased in quantities that will be used during the manufacturer’s recommended time period.
  • Feed should be stored in a dry, cool and pest proof area. Feed should not be stored longer than manufacture’s recommended time period. Weather damaged, moldy, contaminated or old feed should be discarded.
  • Feeding rates should be adjusted according to fish behavior. Fishshould not be overfed (no pellets should be left uneaten), nor should fish be underfed.
  • Daily records of the amount of feed fed, time of feeding and behavior of fish when fed should be maintained.
  • Feed size and amount should be adjusted for growth.

Equipment Management:
• The best affordable equipment should be selected. Spare parts should be easily obtainable. Reputation and location of suppliers should be considered in terms of
customer service and parts availability.
• Manuals for all equipment should be reviewed before installation. All manuals should be retained and stored for easy access.
• A logbook should be maintained to record equipment purchase, installation, maintenance and repair.
• Regular maintenance inspections should be performed on all equipment.  Worn components should be replaced.
• Generators, back-ups for essential equipment, and spare parts should be kept in stock.
• Contingency plans should be drafted for possible equipment failures.
• All personnel should be knowledgeable of equipment operation and location of relevant materials should a disruption occur.

Predator Management:
• Feed containers should be secure and kept out of reach of predators.
• Weed and brush should be reduced around culture areas.
• Where appropriate, trees should be removed to reduce nesting and perching sites for birds.
• Consult with federal, state and local officials concerning restrictions or required permits with regard to predator control or intervention.
• Problem predator species should be positively identified before corrective actions are taken.
• Deterrent systems should be established before predators establish a feeding routine.
• Deterrent systems should include a variety of devices employed at different locations and different times.
• Success of deterrent methods should be monitored and losses to predation should be recorded.
• Seasonal plans should be adjusted when necessary for continued success.
• If deterrent methods are ineffective, kill permits may be obtained from appropriate state and federal wildlife authorities.

Recirculation Systems:
• Full time maintenance with levels of backup is required for a Recirculation System (RAS).
• Alarm systems should be installed for critical factors at appropriate locations such as pump pressure, water flow, temperature, dissolved oxygen, and water level.
• Back-up generators and/or oxygen should be kept available to prevent loss in case of power failure.
• Lighting should be provided when fish are raised indoors.
• UV or ozone filtration is beneficial in some system designs.
• CO2 stripping may be required in a RAS due to high amounts of fish waste and higher stocking densities (> 0.5 lbs/gal).

Recirculation Systems Waste Management:
• Proper feed management should be employed to reduce generation of waste.
• Filtration systems (solids removal and biological filter) should be maintained and monitored on a regular basis.
• Flow from the biofilter to the tanks should be adequate to maintain industry standard water quality parameters for species cultured.
• Solids should be collected regularly and properly discharged.