Northern Ireland

Pet goldfish released into wild 'pose threat to native species'

Goldfish released into the wild have "insatiable appetites" and eat up other species' resources, new research has found. Picture by Margaret McLaughlin
Goldfish released into the wild have "insatiable appetites" and eat up other species' resources, new research has found. Picture by Margaret McLaughlin Goldfish released into the wild have "insatiable appetites" and eat up other species' resources, new research has found. Picture by Margaret McLaughlin

PET goldfish released into the wild have "insatiable appetites" and eat up other species' resources, new research has found.

The study by Queen's University Belfast found that unwanted fish released into lakes and rivers can harm native biodiversity.

Researchers looked at two popular pets in Northern Ireland - goldfish and the white cloud mountain minnow.

The goldfish was first domesticated over a thousand years ago and has established non-native populations around the world.

The research found that goldfish are voracious eaters, consuming much more than the white cloud mountain minnow or native species.

Goldfish were also found to be much braver, a trait linked with invasive spread.

Dr James Dickey from the School of Biological Sciences at Queen’s University Belfast, said that goldfish "pose a triple threat".

"Not only are they readily available, but they combine insatiable appetites with bold behaviour," he said.

"While northern European climates are often a barrier to non-native species surviving in the wild, goldfish are known to be tolerant to such conditions, and could pose a real threat to native biodiversity in rivers and lakes, eating up the resources that other species depend on."

Dr Dickey said popular pet fish species are the most likely to be released.

He said better education of pet owners and "limiting the availability of potentially impactful ones" could help prevent invasive species.