Biosecurity Practices – Essential Considerations for the Pet Fish Industry: Best Health Practices

I’ve arrived in Singapore but before I post my thoughts related to this trip lets finish up the biosecurity series by discussing  the development of best health practices in the context of  implementing/developing a biosecurity plan. TMM

There are husbandry practices that promote fish health and well being, and in so doing help support the principles and goals of a biosecurity program.  These help assure healthy stock that are free of stress and are in optimal condition to resist infection. We will review a few of the key aspects of a quality fish health management program.

Routine and reliable visual assessment of the fish is essential. This may be the first line of defense against disease outbreaks within the tanks. Staff should constantly be scanning the fish populations and looking for signs of outright disease, as well as signs of distress or abnormal behavior, both of which may be the first signs of an impending disease outbreak. Affected animals should be moved to a hospital tank for observation and treatment.

Fish holding systems should be designed so that fish can be easily viewed and captured, yet still have adequate hiding spaces. There should be no edges or objects within the tanks or ponds which might injure the fish. Further, all tanks and life support systems should be easy to maintain and service. If systems are difficult to access and clean then it is likely that staff will tend to avoid the optimal level of maintenance and cleaning.

Staff should also be encouraged to frequently wash their hands, particularly when moving from work areas in one fish holding system to another. Hand washing stations and footbaths, soap or other appropriate disinfectants, and paper towels should be easily accessible so that they will be used regularly.

Equipment cleaning and disinfection stations must also be easily accessible to ensure regular use.  A schedule for regular changes of disinfectants must also be initiated. Most of the common disinfectants are inactivated by organic materials, so these solutions should be changed promptly if they are discolored or dirty, even if it is prior to the scheduled change.

Ensure that staff adheres to the principles of isolation and independence of systems. Reducing the number of systems connected to a single central filtration unit, limiting movement of fish from tank to tank, and striving to prevent cross-contamination via water borne, airborne and fomite transmission will enhance the isolation of fish holding systems.

Anything that might stress fish should be eliminated or minimized.  It is the responsibility of staff to be vigilant for any signs of stress in the fish as well as any aspect of the husbandry or system design that might contribute to stress.  Fish density, water quality, water flow, and tank/pond sanitation should be continually monitored to assure they remain in optimal ranges or conditions. Fish should be handled as little as possible, and when handled, all precautions must be taken to assure that the fish are minimally stressed and not injured.

Nutrition must not be ignored. Foods should not only provide a balanced diet, but they must be handled and stored appropriately to assure their continued quality. Poor quality, contaminated, or spoiled foods should be discarded. Nutrition-related diseases, whether due to nutrient deficiencies or food contamination, can impact immune function in fish, reducing their resistance to infection, and impacting the success of your biosecurity plan.  Care must be taken to assure that all fish are receiving an adequate and complete diet.  Items to consider include:

  • · Insufficient quantity or intake of food will lead to starvation, causing poor growth, poor survival, increased susceptibility to disease, and a loss of reproductive capacity.
  • · An imbalanced diet due to the feeding of one particular food type to the exclusion of all others may lead to deficiencies of certain essential nutrients with diminished survival.
  • · Many diets may not meet the needs of certain fish species that have specific nutritional needs or feeding behaviors. Special diets or supplementation of commercial diets may be necessary.  Seek guidance from those familiar with husbandry of the species or from the literature.
  • · Be wary of poorly formulated diets. This is a rare problem when good quality, commercially prepared diets are used.
  • · Outdated, spoiled, or improperly stored diets will lose nutritional value, and dietary deficits may occur.  These foods should be discarded (Yanong 2001a, Winfree 1992, Roberts 2001).

Dead or sick fish should be promptly culled and examined by trained staff or veterinarians to identify the cause of death or illness so that corrective and preventative measures and treatments can be started. Routine health monitoring of apparently healthy fish may be considered to identify emerging disease issues within a facility before they become a serious problem.

During the daily work routine, staff should address the needs of the most susceptible fish and their holding facilities first, moving to the fish with the highest probability of carrying disease last. Typically this means that the display fish are cared for first, starting with the youngest and moving to the oldest fish. Then staff go to systems holding fish under quarantine. Finally, any hospitalized fish or fish undergoing treatment are attended to. These workers should not go back and work with display fish until the next day. If not possible, that individual should wash well and perhaps change clothes after working with quarantine and hospital fish. Alternatively, facilities may opt to designate one individual that only works with animals under quarantine and treatment and never works with display or holding fish.

Quality Management

A quality management program (aka quality assurance, quality control) is an integral part of any biosecurity plan. It will help assure that the biosecurity practices that are established for a facility are actually put into place and followed.  It is essential that biosecurity practices are used consistently and accurately, and are not just brought out when they are remembered or might help control a problem.  The quality program will instill a sense of routine to the biosecurity procedures, and will assure that employees use the procedures correctly. It also provides a means of checking and verifying. Quality management concepts should permeate all aspects of the biosecurity protocols.  Quality management is the key to a successful biosecurity program.

The basic components of the quality program include written standard operating procedures, training, record keeping, accountability, and audits.  All are important, and none can be neglected.


A biosecurity program is essential to successful fish production and husbandry. The components of the program address exclusion of pathogens, control of pathogens, and good health practices, and assemble to provide a security system that will help minimize the impact of disease on a fish facility. A successful biosecurity program requires commitment by management and staff to follow operational policies and procedures, continually assess those protocols, and modify them as necessary. A good biosecurity program protects the business by protecting the animals and the customers. Finally, remember that each biosecuity program is tailored to each specific facility. Protocols are developed based upon the diseases risks associated with a particular facility  or market sector, financial and human resources and  facility design limitations.  Remember that implementing some biosecurity protocols is always better than doing nothing. It is always more expensive to implement a biosecuirty plan after a major disease event.

I look forward to your comments.  TMM