In the Wild, Goldfish Turn From Pet to Pest

NY Times:

In the Wild, Goldfish Turn From Pet to Pest

Two decades ago, someone dropped a handful of unwanted pet goldfish into a creek in southwestern Australia. Those goldfish grew, swam downstream, mucked up waters wherever they went and spawned like mad. Before long, they took over the whole river.Researchers from Murdoch University believe this scenario, or something like it, is the cause of a feral goldfish invasion in Australia’s Vasse River. Since 2003, they have been running a goldfish tracking and control program that involves catching fish along the length of the river, freezing them to death and studying them in the lab. Despite this program, goldfish in the Vasse are thriving, with some fish growing as long as 16 inches and weighing up to four pounds — the size of a two-liter soda bottle.

Goldfish are one of the world’s worst invasive aquatic species, with outbreaks also having been reported in Nevada, Colorado and Alberta, Canada, in the last several years. Goldfish in the Vasse River, though, “have the fastest known growth rate of goldfish in the world,” said Stephen Beatty, a researcher at Murdoch University who helps lead the control program. If his team gets the Vasse’s goldfish problem in order, its work could inform goldfish management efforts far beyond Australia.

Goldfish invasions start with a disconnect between how people view goldfish and what goldfish are like in the wild, Dr. Beatty said. “Once you introduce something into a new environment — even if it’s a cute, cuddly aquarium fish — it can have quite unexpected, serious biological consequences.”
The goldfish is a domesticated carp, first bred in ancient China for ornamental gardens. For centuries, goldfish were prized symbols of luck and fortune. Shortly after they made their way to the United States in the mid-1800s, however, they transitioned from the exotic to the mundane.

Geez, first rabbits, now goldfish.

Not really fired up about this issue. Just facinates that someone described a goldfish as cuddly. They do know a goldfish is a fish right? With scales, underwater and no fur right?

In other news I recently read about a 500 dollar surgery on a goldfish.

The water version of the Aussie rabbits of the 1800s.

Are goldfish worth catching?


Since people are starving to death in Burundi and Sudan, can’t fish and rabbits be sent there for food?

Sure but who’s to pay for transportation?

I ate a live goldfish in college for a 20 dollar bet. It wasn’t my best decision ever…

According to the article it just takes a “handful” to stock a river…

If they are ediblle they could become a niche delicacy if some famous chef catches on.


Yes, that is not a humane way to get rid of aquarium fish.

The RSPCA of Australia recommends three different methods: anesthaetic, clove oil, or decapitation followed rapidly by pithing the brain.

The drawback to the first is that a veterinarian will likely need to be involved. The drawback to the last method is that it is not for the squeamish or to those who might hesitate. Clove oil, on the other hand, is an expense but relatively pain-free.

Clove oil is a sedative which at high doses, can be used to euthanase small fish. Unlike veterinary anaesthetics, clove oil is readily available from most chemists. Around 400 mg of clove oil per litre of aquarium water is sufficient to cause death in exposed fish. The clove oil should be mixed with a little warm water first before adding it to the water and fish slowly. Do not add all at once as fish get excited - add the clove oil mix over a 5 minute period.

When exposed to clove oil at this concentration fish quickly lose consciousness, stop breathing and die from hypoxia. Please note that the concentration of the solution must be appropriate and the fish must remain in the solution for at least 10 minutes.

Studies have found clove oil to be similar to the anaesthetics MS-222 and Benzocaine hydrochloride.

Is there an appropriate emoticon for this? :bigyikes: Not the one I wanted but it will suffice :wink:

Reminds me of the old Burl Ives song… " I know an old lady who swallowed a fly." One of my all time childhood favourites

Oh my! I couldn’t help but laugh! :rotfl:

I can just imagine this little fish on a big plate somewhere, for haute cuisine!

On the other hand–on a serious note–I totally agree with the way these poor little fish are killed…

Freezing them to death? That’s sad. :frowning:

We shouldn’t try to humanise them. They are, after all, cold blooded.

I imagine getting caught and then cooked is not comfortable for them, either.


I immediately thought it was sad, but, perhaps they froze them by tossing them in liquid nitrogen instead of going the slow and painful route.


Just had my lunch too…:frowning:

I wonder where all the predators are in these goldfish-infested waters. Some people use them for live bait to catch the really voracious predators like bass. I realize if they get to be three-pounders, that’s something else. But still, I can’t imagine the river otters in the creek next to where I grew up leaving a three pound fish of any kind go unmolested. Same with eagles. The “in betweeners” would, I think, be snatched up by the herons and kingfishers.

Goldfish are a species of carp, and carp have been known to infest some US waterways, despite an abundance of predators.

I am not familiar with the situation in Australia, but apparently the problem of invasive carp is so out of control that the government is planning to seed some rivers with herpes virus to kill the carp.

Round these parts we use guns, bats, and even bows to get rid of an invasive spiciest of carp. It’s a little more effective than freezing them.

I always thought you could freeze a goldfish and it would reanimate when thawed. I’ve never seen that tried though. Perhaps it’s an urban legend.


Can’t the fish be captured and released elsewhere? The human world desperately needs protein.


Maybe we can do that with all pests. Gophers for Ghana. Rats for Russia. Whistle pigs for wester Sahara, locusts for Libya.

The problem is when you introduce a foreign species to a foreign ecosystem. More likely than not you will kill more than you save. But we are supposed to be an open boarders people so…:shrug:

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