Self-Cloning Monster Goldfish Are Invading Canadian Waters

By: Lydia Iseh | Published: Nov 12, 2023

Many people often keep goldfish as pets, and it’s not hard to see why. Besides being a sight for sore eyes, goldfish are as intelligent as they come; it makes them such well-appreciated guests to have in small ponds, fish bowls, and aquariums. But if you think it’s all glee and fun with goldfish, think again. These aquatic animals are quickly becoming a menace in Canadian waters.

Canadian goldfish owners are starting to rethink as these adaptable pet fish have become a cause for concern by becoming self-cloning monsters. Let’s get into the details.

It All Started With Pet Owners

Having a pet fish as a household pet is considered normal all over the United States and Canada. It is, in fact, the third most popular pet choice after dogs and cats.  


Source: Wikipedia

Unfortunately, unlike cats and dogs, there is no binding agreement to strengthen the responsibility of owning a pet fish. This means that people can easily abandon their pets when they decide they have become too big a responsibility. 


They Quickly Outgrow The Aquarium

Owners of monster goldfish are known to tolerate the animal until it starts outgrowing its tank. When this happens the owner may decide to dump the overgrown fish in a nearby waterbody. 


Source: Fisheries and Oceans/Twitter

Some even go as far as flushing them down the toilet, which reportedly just makes them tougher. When the fish is released into the wild like this, it transforms from a home pet into an invasive specie capable of self-cloning and dominating lakes. 

Self-Cloning ‘Monsters’ in Our Waters

No alien movie is complete without that zealous scientist who sounds the warning. It turns out, that’s exactly what happens in real life too. In a recent report, Ashley Joannou of the CBC raised the alarm over the monster goldfish. 


Source: Inside Edition/ YouTube

Her report about British Columbia claims that “thousands of large, invasive goldfish have multiplied in bodies of water around the province.”

They Are More Harmful Than They Look

Is it that big a deal? Absolutely. Many people who dump their pet goldfish into nearby ponds or lakes may think they are doing them a favor by releasing them back into the wild but this is wrong. 


Source: Mashable

In truth, putting goldfish into environments they are not native to can have negative consequences. This has to do with how fast it can reproduce. 

They Survive Harsh Conditions

They may look harmless, but these fishes make the saying “never judge a book by its cover” more accurate. The monster goldfish can not only reproduce rapidly, but it is also able to tolerate harsh living conditions. 


These special abilities the goldfish possesses makes them powerful invaders that can easily crowd out other native species of an area. 


They Are Voracious Eaters

Goldfish are big eaters that can easily degrade a wetland habitat. They make things more difficult for other aquatic creatures by stirring up mud that clouds the water. Other creatures will find it difficult to breathe as a result.

Source: Fisheries and Oceans/Twitter

These fishes can also lead to the infestation of foreign parasites and diseases that can cause harm that will be felt all through the ecosystem. 


They Can Reproduce Rapidly

These and many other unnamed reasons make the goldfish a threat if they are dumped indiscriminately in waterbodies. It also does not help matters that they release eggs each time there is a temperature change. This means that if the water temperature rises earlier due to climate change, they will reproduce faster.

Source: Lone Star Outdoor News

According to Joannou’s report, the goldfish can release up to 50,000 eggs at the same time. That is already a whopping amount but what is more shocking is that this process is replicated thrice in one summer. 


Females Can Clone Themselves

It barely makes sense but it gets worse. Apparently, the female goldfish do not need to have a male around to reproduce. 

Source: Ebay

According to Natural Resource Sciences professor Brian Heise, “They have a special process called gynogenesis in which the female will get the sperm from a different kind of minnow … to start the eggs developing, even though they’re not fertilized. And so she produces clones of herself. So, they’re very good at spreading rapidly.”


They Grow As Large As Footballs

It is also worth mentioning that the monster in the name “monster goldfish” has nothing to do with what they eat or their behavior and everything to do with their size. 

Source: YouTube

Monster goldfish can grow to be as large as a football. These are not weak fishes that are too small to survive out there. These are the biggest and most adaptable fishes that grew too big for the tanks humans put them in. 


Even Winter Won’t Stop Them

Some may think that they are fragile because of how beautiful they look. However, it would be wrong to underestimate these monster goldfish. 

Source: daPA/YouTube

Canada experiences intense winter that freezes over its lakes and ponds, a phenomenon that affects weaker fishes. But not the goldfish. 


Electrocution or Electrofishing?

To prevent them from dominating Canadian waterbodies, people have resorted to all sorts of methods including electrocution. Biologists now call the process “electrofishing” and it involves “shocking” the water by passing an electric current through it to stun the fish. When they are stunned, they float up to the surface of the water where they can be scooped up with a net. 

Source: hero3066/YouTube

The process is generally effective, however, according to the CBC, it costs a lot of capital. Just a couple of days doing it can cost up to $10,000/= for each lake treated. Many who live stateside have also reported sightings of large schools of goldfish in ponds. One witness claimed they saw a school of up to 100 tiny goldfish in a pond located on a municipal golf course which just shows how fast they are spreading. 


Do Not Dump Them Indiscriminately

Although goldfish look tiny, beautiful, and harmless, they grow bigger and start rapidly self-cloning, becoming dangerous to the ecosystem.

Source: Fisheries and Oceans/Twitter

The best way to deal with this growing invasion is to ensure that many pet owners are aware of it. If for any reason a pet goldfish is no longer wanted, it is advisable to see an expert on the steps to take. Do not dump them carelessly and never flush them down the drain.