Friday, April 8, 2016


Giant goldfish caught in Tommy Thompson Park in Toronto.  Former pet goldfish released into wild waterways can grow to exceptional sizes. This was found during a fish survey.  (Photo Toronto and Region Conservation Authority. )
Giant goldfish caught in Tommy Thompson Park in Toronto. Former pet goldfish released into wild waterways can grow to exceptional sizes. This was found during a fish survey. (Photo Toronto and Region Conservation Authority. )
Giant goldfish invading Alberta ponds

Lethbridge – Pet goldfish are small adorable littlefish that can be purchased for a nominal price at a local pet shop.
In fact, most people would not think of them as an environmentally disrupting invasive species. That said, a number of pet owners have grown tired of maintaining the fish and rather than flush them down the toilet, they do what they believe is the humane thing to do: set them free in the wild.
As per Kate Wilson, an aquatic invasive species specialist with Alberta Environment and Parks, that assumption is a big mistake.
Wilson points out that the cute little fish get controlled feedings inside a goldfish bowl. Set free in the nation’s waterways, they never get enough food to satiate themselves. This causes them to grow and grow.
“A fish wouldn’t survive being flushed through the water treatment system, but those diseases and parasites that we talked about could potentially survive the process and end up being discharged into rivers and lakes,” explains Wilson. “We are not advocating that even dead fish be flushed.”
Authorities are now finding giant goldfish the size of dinner plates. Not only that, the goldfish are resilient. They are fully capable of living in cold waters with little oxygenation. At this time, authorities believes hundreds of thousands of goldfish are inhabiting the nation’s waterways eating and breeding. Bear in mind, goldfish are not native to the nation’s waters and as such have no natural predators to check their population growth.
Sarah Cicchini, an environmental coordinator with the city of St. Albert, says that city’s goldfish problem started last summer, when a concerned citizen alerted officials that the popular pet had taken over a stormwater pond.
They investigated and found hundreds of goldfish.
“Some were probably finger tips to elbow [in length],” Cicchini said.  “I remember looking at a few and being like, ‘Oh, you’re like my arm.’”
Authorities remind citizens that it is against the law to take living fish from one body of water (E.g. a fish bowl) and transfer them to another body of water such as a river, stream, lake, etc. While everyone understands the desire to prevent the fish from being harmed, the solution in dealing with them is to see if they can be returned to the pet shop. Alternatively, goldfish owners can try handing them off to someone they know or donating them to a school. If that doesn’t work, contact a veterinarian to see how to euthanize them in a kind manner.

Aquarium Owners

Water gardeners, pond and aquarium owners have a number of responsibilities, including:
  • taking good care of the species that they keep
  • ensuring their artificial water environment stays isolated from the outside environment
  • when necessary, disposing of the fish or plants from that environment in a safe and humane manner
Do not dispose of plants and fish from aquariums and ponds into an Alberta stream, lake or river system. Releasing them disrupts the natural balance of Alberta’s ecosystems, and ultimately results in biodiversity loss.
For example, koi and goldfish released from ponds and aquariums can survive Alberta’s climate and grow to be very large. They have no natural predators in Alberta and will out-compete native species for resources.
It is illegal to release live fish into Alberta’s lakes or rivers. Fines can be up to $100,000.
If you are no longer able to care for a fish from your pond or aquarium, do not release it into a lake or river. Try:
  • Contacting the retailer for advice, or for a possible return
  • Giving it to another aquarium or pond owner
  • Donating it to a local aquarium society or school
  • Talking to a veterinarian about humane disposal


Do not transfer live fish from one water body to another.
  • It is illegal to move live fish from one water body to another. Doing so disrupts the local ecosystem, threatens the existing fish population and, if a stocked fishery, jeopardizes the future of that fishery.
  • Fish that are illegally released into a stocked fishery can undermine efforts to maintain that fishery for the enjoyment of all Alberta anglers.
  • Once an illegal introduction has occurred in a stocked fishery, the efforts to restore it are extremely expensive and can bring some harm to other parts of the local ecosystem.
  • Penalties for illegally transferring fish into any water body aside from the one it was caught in can be up to $100,000 and/or a year in prison.
  • Fish introduced from outside of Canada can cause significant damage to local fish populations. Though not currently found within Canadian waters, the silver and bighead carp are threatening to find their way to the Great Lakes. These fish, introduced into US waters from Taiwan, are voracious eaters and out-compete native trout and salmon. These carp are also known for their capacity to leap out of the water, creating a hazard for water skiers and boaters.
  • To prevent the introduction of invasive worm species put unused bait back in its original packaging and put it in a garbage container.
  • Do you wear waders when you fish? Felt-soled waders are highly absorbent and, if not properly cleaned, can transfer invasive species from one water body to another. Soak them in hot water for at least 40 minutes after every use, or better yet, switch to non-felt-soled waders.