Cookies on Animal Science Database

Like most websites we use cookies. This is to ensure that we give you the best experience possible.


Continuing to use  means you agree to our use of cookies. If you would like to, you can learn more about the cookies we use.

Animal Science Database

Supporting your research in animal production, welfare and health

Animal Science is now available on our new platform, CABI Digital Library. Please note that this website will be discontinued in mid-December, and all access will be automatically redirected to CABI Digital Library.

Take a look at Animal Science on CABI Digital Library. 

News Article

Live pet fish flushed down the toilet can pose a threat to wild, domestic fish stocks

Certain exotic diseases take longer to manifest than the quarantine period

Ornamental pet fish owners in Australia are being advised not to abandon them to the wild should they decide not to continue keeping them.  

According to Dr Joy Becker, lecturer in the Faculty of Veterinary Science at the University of Sydney, about 18 million ornamental fish are imported each year, some of which pose a disease threat to domestic fish stocks in aquaria, fish farms and wild fish.

Goldfish and the dwarf gourami from Southeast Asia are the most popular imported ornamental fish in Australia.

Strict Australian health controls exist including the requirement for a certificate of good health from the exporting country and quarantine periods for the imported fish.

While current fish disease detection methods are good it remains a challenge to detect some serious exotic diseases, according to Dr Becker. One reason, she said, is that some diseases take longer to emerge than the duration of the quarantine period imposed.

Dr Becker has researched two diseases in imported fish, the dwarf gourami iridovirus (DGIV) and cyprinid herpesvirus 2 (CyHV2). Although CyHV2 infects goldfish and is a problem for the domestic industry, it does not infect other fish species. DGIV, however, affects other fish species, killing Murray cod in Victoria in 2003. DGIV appears to infect both freshwater and marine fish species.

She examined ornamental fish that were newly imported and in quarantine, pet stores and wholesalers, as well as domestic ornamental fish in aquaculture farms and in the wild.

Though DGIV was not expected to be present, it was found in 20 percent of gouramis still in quarantine and approximately 15 percent of fish at wholesalers, recently released from quarantine. The virus was found in 30 percent of sick gouramis at pet shops and at a domestic fish farm.

CyHV2 was not only found at wholesalers and fish farms but also in wild fish stocks.

A major concern, according to Dr Becker, is that people release their fish into local waterways, including rivers, dams and fountains in public areas, or flush live fish down the toilet in areas where wild fish stocks are at risk.

Most people are unaware that fish can survive being flushed, which is one reason for the presence of feral populations of goldfish in many temperate parts of Australia and feral gourami in the northern more tropical waterways in Queensland, she said.

The key message, according to Dr Becker, is not to release pet fish into the wild and, if giving a pet fish as a present, to remember that the lifespan of a goldfish or dwarf gourami can be many years.

Individual fish owners are only one part of the problem, she emphasised, adding that they have to be more effective at stopping diseased fish entering the country, especially those carrying the dwarf gourami iridovirus.

Article details

  • Date
  • 23 December 2013
  • Source
  • University of Sydney
  • Subject(s)
  • Aquaculture
  • Veterinary medicine