Stop dumping your pet fish, they’re growing into monsters

If you thought that dumping your pet fish into your local waterway was a good idea, think again; they are growing into actual monsters.

This is one of the many instances where “out of sight, out of mind” really doesn’t work well.

As a general rule of thumb, when a species is introduced into an ecosystem it is going to cause problems – free from natural predators, the introduced species will deplete the ecosystem’s resources and kill native species.

It has happened time and time again; goats on the Galápagos Islands, Asian carp in the Great Lakes, and the New Guinea flatworm in Europe. And come on, the only reason Australia has cane toads, rabbits and camels is because they were all introduced! But now, according to a new study, the humble goldfish is Australia’s next biggest problem.

Dumped into waterways, the former pets are growing to become scaly monstrosities weighing in at 2 kilos. This is causing a range of problems including the disruption of sediment, the introduction of new diseases and the depletion of resources as the goldfish munch away on other animals (they are carnivorous in the wild).

Stephen Beatty, from the School of Veterinary and Life Sciences at Perth’s Murdoch University, explained the crazy phenomenon:

Perhaps they were kids’ pets where the family have been moving house, and their parents, not wanting to take the aquarium, have dumped them in the local wetlands. Unfortunately, a lot of people don’t understand that wetlands connect up to river systems, and introduced fish, once they get in there, can do a lot of damage to native freshwater fish and the aquatic habitat.

Australia isn’t the only place with a problem. The hazardous effects of domestic goldfish in waterways have already been seen in Canada and the US.

“The key thing is if you’ve got unwanted pets, you can see if the pet shops will take them back. But if you’re going to euthanise them, putting them in the freezer is the most humane way,” added Beatty.

When you consider that fish that were tracked as part of the study were found to have travelled up to 228 kilometres a year, you can understand why the problem has spread so rapidly.

Hold on to your goldfish!

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About the author

Cormack is a Melbourne based freelance writer and photographer. He loves to travel, drink red wine, and spin records. On the weekends you’ll most likely find him eating pork buns or shaking up cocktails for his friends.

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