5542 Engineer Dr.
Huntington Beach, Ca 92649
Importation of Diseases with Ornamental Fish:
by Dallas E. Weaver, Ph.D.
At the present time we are importing on the order of 10,000
boxes of live ornamental fish per week via air freight from at
least 20 different countries and 500+ different source locations
or farms. Along with all these desirable animals, there are bound
to be undesirable organisms such as parasites, pathogenic bacteria
and viral diseases. The existing inspection system by the Customs
Department, Fish and Wildlife, and the local Fish and Game Commission
(in California) does not have the technical expertise even to
identify the species of fish relative to what is on the bill of
lading, let alone to inspect for microscopic disease organisms.
The time elapsed between when a fish is imported and when
it is for sale in a major pet shop chain is less than 48 hrs.
Imported animals carrying disease organisms can come into this
country and be sold to the final consumer, well before any disease
would become apparent. To compound this problem, typical tropical
fish wholesalers and retailers have no bio-security procedures.
They utilize common recycle water systems, with inadequate or
improperly maintained UV's, which spread organisms to all
uninfected animals. The typical wholesaler uses antibiotics and
other treatments in an attempt to keep the fish alive long enough
to sell to the retailers who often also use various treatments.
It is clear that this existing distribution system contains
significant elements of risk. These risks should be examined to
determine if they are acceptable risks.
The risks associated with the existing ornamental fish importation system can be broken into the following categories according to
the group which will be impacted:
Risks to the ornamental fish industry
Risks to the aquaculture industry from imported diseases
Risks to the aquatic environment from imported diseases
Risks to the public health and animal health from imported anti-biotic resistances associated with the diseases.
Ornamental Industry Risks:
The tropical fish industry has been unsuccessfully dealing
with the imported disease problems for at least 25 years. In the
late 60's and early 70's, angel fish (Pterolphyllum
scalare) were the dominant imported fish and enjoyed wide popularity.
A disease spread from Asian imports to the US producers and customers
and virtually eliminated angel fish from the market place. To
this day, it is only possible to obtain "clean" angels
from private breeders and wholesalers who keep them in isolation
tanks in an effort to prevent infection. The identity of the actual
infectious agent is not clear and we don't have any tests
to determine if a stock is "clean". Domestic breeders
come and go as they start new systems and do well for a few years
and then everything dies. The disease from Asia has destroyed
a multi-million-dollar part of the pet business.
In the mid 80's, fancy male guppies were a very major
product. Every wholesaler carried 10 to 30 strains of these beautiful
fish, with most retailers having several tanks and a wide variety.
Most of these fish were imported from Singapore and other Asian
sources. In the late 80's to early 90's, the mortality
rate increased, and it became clear that they were carrying an
infectious agent which would spread to domestic produced guppies
with lethal consequences. Exposure of healthy domestic produced
guppies to Singapore fancy guppies resulted in near total mortality
within a few days. No treatments seemed to be effective, and the
problem continued to get worse with the imported guppies. It became
impossible for a wholesaler or retailer to carry Asian guppies
in the same system with domestic produced guppies without the
domestic guppies becoming infected and experiencing almost total
mortality (the Asian guppies had high but not total mortality
and appeared to have some resistance to the unknown agent). As
a result, the domestically produced guppies were excluded from
the market, and major pet retailers dropped items like common
guppies and feeder guppies.
The guppy disease problem continued to worsen until it got
to the point that importers could not get fancy guppies from Asia
to the US alive, and the wholesalers could not keep them alive
for even 48 hrs. At this point, fancy guppies ceased to be a viable
product and were no longer imported in significant numbers. Meanwhile,
the quality of Florida-produced guppies decreased creating high
mortality problems at the retail level. This mortality problem
has prevented the domestic producers from filling the market.
Whether the problems with the Florida guppies came from and are
the same as thoes associated with the Singapore guppies has not
In the early 90's, many of the Asian produced Gouramies
began to exhibit mortality problems at the wholesale and retail
levels. This was identified as an iridovirus. Some countries,
such as Australia, tightened their quarantine of imported Asian
Gouramies (three weeks without medication). There were no restrictions
on the US importation, and within a few years, several very major
Florida Gouramie producers failed due to high mortality problems
caused by an iridovirus. Without DNA analysis, it is not known
that this is the same strain and that it was transferred to the
Florida producers from imported animals. However, the timing makes
one suspicious of the imported animals as the source.
All these problems are internal to the pet industry and
create problems directly for a number of relatively small businesses.
However, the overall industry is also hurt by the loss of customers
who can't keep the fish alive and quit trying. These phenomena
may account for the apparent slow sales in the industry.
Aquaculture risk from imported ornamental fish:
There is an obvious risk that one of the imported diseases
could infect some aquaculture species. Most of the imported bacterial
diseases from Asia have multiple anti-biotic resistances and are
totally immune to any of the legal treatments allowed by the FDA.
How real is this risk that a disease of imported ornamental fish
could reach the commercial food fish industry?
Apparently an iridovirus created a problem for some tilipia
producers in Idaho. This problem was traced back to Florida fingerling
producers. Is this the same strain that destroyed Florida's
Gouramies producers and the Asian Gouramies producers? We don't
know at this time. However, it is a distinct possibility.
We do know that Yersinia ruckeri (enteric redmouth in trout
- ERM) has been identified in Florida in Gouramies that originated
in Asia. There was no conformation of this analysis and the fish
were destroyed, in an attempt to protect the rest of the hatchery.
Verbal reports indicate that ERM was also identified in trout
in Scotland and traced back to Gouramies from Asia in the ornamental
Multiple anti-biotic resistant strains of Edwardsiella tarda
have been reported in imported ornamental fish (B. Dixon). This
pathogen is known to infect catfish along with many other aquaculture
species (J. Plumb). One of the imported strains of E. tarda could
relatively easily get started in the catfish industry. Given the
size of the catfish industry, the relative significance of this
industry in Mississippi and Arkansas and the present political
leadership, the risk of a political reaction leading to the shutting
down of all imports and ornamental fish movement is real. Bio-security
in the catfish industry is not high enough to stop the distribution
via birds and equipment. This risk is real for both the catfish
industry and the ornamental industry.
Clearly some of the same analyses and diseases apply to
the stripped bass and tilipia industries. However, they aren't
as politically powerful as the catfish industry. The impact of
a disease being traced to ornamental fish would not be as significant
to the ornamental fish industry. Individual aquaculture producers
may be destroyed, since they would have no legal means of treating
the anti-biotic resistant diseases.
In summary, imported ornamental fish present a significant
risk to aquaculture.
Environmental risk from imported diseases:
The risk to the environment associated with iridovirus in
Asian produced Gouramies was one of the prime driving forces behind
the tighter quarantine being applied to Gouramies in Australia.
The risk to wild stocks from some of these imported diseases is
If something did cause an environmental problem, the environment
will pay the price.
Hunan health risk:
The FDA has used the risk of development of anti-biotic
resistance to block the use or possible use of flouroquinolone
on fish. The FDA's theory is that the use of this class
of drugs by aquaculture and ornamental fish producers could result
in the target bacteria developing resistance. This resistance
could than be transferred to human pathogenic bacteria thereby
eliminating one of our last lines of defense against these human
The ban on flouroquinolone in this country will have no
impact on Asian fish producers. It is understood that several
countries are using flouroquinoloneís without limitations
on ornamental fish. If the FDA's analysis is correct, the
ban on flouroquinolone will not solve the problems, which will
be imported along with the ornamental fish.
Cost and impacts of various risk minimization
Various approaches can be taken to decrease the previously
covered risks. An obvious approach would be to ban all imported
aquatic livestock. However, a ban would result in a significant
decrease in the variety of fish being sold and could decrease
the customer base. This action would favor the large pet shop
chain which only carry the basic high volume fish, most of which
are also produced in the US. The lack of variety would hurt the
small and specialized ornamental fish store, which would no longer
be able to carry products that the chains don't carry.
There would probably be a minor price increase to the final customer
as the higher cost US producers fill the market that is now controlled
by the Asian producers. With the farm gate price of ornamental
fish being only about 10% of the retail price, a large increase
in the farm gate price would not necessarily cause a large retail
A preferable approach would be to impose a mandatory quarantine
on imported ornamental fish. This approach is used in most of
the world, with the US being the exception. Australia and New
Zealand both have quarantine requirements for all imported ornamental
fish. Considering the 10,000 boxes of fish that are imported every
week, we are only talking about 10 tons of actual fish per week.
If we required holding for 3 weeks, we would only have to hold
30 tons of fish. Since we aren't growing the fish, they
would only be feed about 300 kg/day. Relative to any large commercial
aquaculture facility, this is an insignificant amount of fish
or feed. The cost of a 3 week quarantine would not be excessive,
especially when you consider that the producer has already held
the fish for 20 to 30 weeks. In terms of time, we are adding about
10% to the time to sale for a fish, which will only add a similar
percentage to the wholesale price of the fish. If the fish can
not be held for 3 weeks in the distribution system, the quality
isnít good enough to sell to the final customer.We expect
the final customer, with even less knowledge than the wholesaler,
to keep the fish alive for 50+ weeks.
Heath documentation approaches have been used with imported
food animals. These control systems require inspection in the
exporting country for specific disease organisms and ban the importation
of animals infected with these specific organisms. On paper, this
would be a less costly and very effective approach to the problem.
However, unlike salmon, ornamental fish come from many less developed
countries where a few dollars can get any type of documentation
desired, independent of the real health status of the animals.
Source country documentation wonít work in the ornamental
industry. This approach only works with known and well defined
diseases and has trouble controlling a very virulent strain of
a common pathogen which would not be one of the reportable organisms
or organisms of concern.
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