general resistance

Over forty years ago, I bred and bred Dwarf Gouramis for the first time. At that point, they could reasonably be described as a hardy fish. Unfortunately, the ones we have today have lost much of this resistance. This loss of stamina seems to have been caused by a number of different things.

They have been selectively bred, producing a number of different color variations. It is likely that many of these are inbred and suffer from the lack of vigor often caused by inbreeding.

Most dwarf gouramis bred in places like Singapore will have been kept under controlled conditions, and individuals that would have become rapidly extinct in the wild will have survived and often been used for breeding. Related to this is that in captivity it would have been selected for rapid growth, and particularly rapid growth under quasi-force diets fed to commercially bred fish. Fast growing fish are often not as hardy as wild ones.

illness

Related to the lack of resistance in many commercially bred dwarf gouramis is the fact that many of them are diseased. They are susceptible to normal aquarium fish diseases, but one is of particular concern. This is the

Dwarf gourami iridovirus.

This disease kills dwarf gouramis slowly, sometimes taking up to a year to kill them. Symptoms include wasting of the fish and there is no doubt that before this disease was identified, tuberculosis of fish was blamed for some of the deaths from this virus. This virus may have become a problem due to the extensive inbreeding of this fish in Singapore.

Many viral diseases are specific to a single species, and it is frequently reported that only dwarf gouramis can contract dwarf gouramis iridovirus. However, there are also many conflicting reports.

A study by a team led by Professor Richard Whittington of the University of Sydney, Australia, found a 99.95% genetic similarity between the Dwarf Gourami Iridovirus and a 2003 virus outbreak that killed Murray Cod, Maccullochella peelii peelii. One test showed that Murray Cod can be infected with the Dwarf Gourami iridovirus and had a 90% mortality.

There is fear that the Mosquito fish (gambusía species) can act as a carrier of this virus and help its spread through wild fish populations. This virus has also been reported to affect swordtails.

One of the problems with these reports is that there are many types of fish iridoviruses. Some of them will kill or make fish sick, while others appear to have no negative effects on fish. To really find out what is going on would require a huge investigative effort.

Various internet articles say that 22% of dwarf gouramis leaving Singapore have this virus. This figure is actually based on a study of Dwarf Gouramis in Australian retail aquarium stores. The study found that 22% of these fish were infected with this virus. All the fish tasted had been imported from Singapore. A fairly reasonable leap was made to claim that 22% of dwarf gouramis leaving Singapore were infected.

Of course, all the fish tested would have been quarantined and any fish showing signs of disease would have been destroyed. If any batch of fish had many diseased specimens, the entire batch would have been destroyed. If an importer loses an entire batch of fish, he has lost a lot of money and would look for another supplier.

At least one reputable website says that most fish leaving Singapore are infected. 22% is a very worrying number, but certainly not “the majority”.

Government action is needed now!

The ornamental fish trade is an important part of Singapore’s trade. If there is such a serious problem with Singapore fish, it needs to be fixed.

A few years ago, a large ornamental fish farm in Australia had a serious problem with a fish disease. With government help, they systematically eradicated the disease. This fish farm now has a very good reputation for the quality of its fish. Unfortunately, they do not breed dwarf gouramis.

The Singapore government must recognize that there is a serious problem and solve it before Singapore’s fish export trade is ruined.