Throwing Goldfish in Rivers May Result to Ecological Disaster, Experts Warn Pet Owners

If that lockdown goldfish is starting to lose its luster, think carefully before tossing it in the river or canal - the critters may appear harmless. Still, their ravenous appetites, cold tolerance, and go-getter attitudes may be disastrous for local fauna compared to native species.

(Photo : Wikimedia Commons)

Aggressive Consumers

According to a new study, goldfish consume far more than equivalent fish in UK waters, consume more than other invasive fish, and are far more eager to take on other species aggressively.

According to the study's principal scientist, Dr. James Dickey of Queen's University Belfast, goldfish are a triple danger.

He explained, "Not only are they easily available, but they also combine ravenous cravings with daring behavior." "While northern European climes are a barrier to non-native species living in the wild, goldfish are tolerant of such circumstances and might represent a danger to native biodiversity in rivers and lakes by using the resources that other species rely on."

Also Read: Young Boy Caught a Massive "Foot-Long" Goldfish, Proving Invasive Goldfish Epidemic

Being Released

(Photo : Wikimedia Commons)

Although anecdotal accounts suggest this may be the case, the study could not determine if pet owners who purchased new goldfish during lockdown were more likely to release them into the wild.

"While our research did not look into whether the problem has gotten worse since lockdown, there is reason to suspect that it has, or will," Dickey added.

"Recent news articles concerning released Amazonian catfish discovered in Glasgow may be related." There's also possible a time lag, and we won't notice the impacts until this summer, when normalcy returns and, for example, people want to vacation [and leave their dogs behind]."

The study, published in the journal NeoBiota, looked at the two most regularly traded fish species in Northern Ireland: goldfish, a globally invasive species, and the white cloud mountain minnow, which has yet to establish a significant invasive foothold. Both species are endemic to East Asia and belong to the carp family.

Intense Examination

By examining availability, feeding rates, and behavior, the researchers developed a unique way of analyzing and comparing the impacts of both species. Goldfish outcompeted the white cloud minnow by a wide margin, demonstrating that they can wreak havoc on local animal populations in UK ponds, rivers, and streams.

When goldfish are put into UK rivers, they feed on tadpoles and other tiny fish, upsetting natural ecosystems.

Due to their adaptability, goldfish have grown to over 30cm (1ft) in length in various streams in the United States.

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Many pet owners believe that releasing their goldfish into the wild is a kind deed, but Dickey warns that it is detrimental.

According to the study, another approach to lessen the damage is for pet stores to carry more alternative species that do not represent such an invasive risk.

"Goldfish are a high-risk species," Dickey explained. "A way to avoiding destructive invaders from establishing in the future is to limit the availability of potentially impacting [species, such as goldfish] alongside increased education of pet owners."

Do Not Flush

According to Dickey, flushing an unwanted fish down the toilet is likewise a no-no. However, he claims that certain pet stores will accept fish for return, albeit not always with a refund, and that there are websites like Preloved.co.uk where they may be given away or exchanged.