The harmless-looking goldfish is so voracious that attempting to save its life by releasing it into the wild could be “catastrophic” for native biodiversity, a new study suggests.

A study by Queen’s University Belfast (QUB) scientists assessed the ecological impact of the pet fish if released into the wild by comparing it to the white cloud mountain minnow.

The goldfish and white cloud mountain minnow are the two most commonly traded fish species in Northern Ireland.

The goldfish has established non-native populations around the world since it was “domesticated” a thousand years ago.

By contrast, the white cloud mountain minnow has a limited invasion history to date, the QUB researchers point out.

This study published in NeoBiota – a website for the European Group on Biological Invasions - showed goldfish to be “voracious, consuming much more than the white cloud mountain minnow or native species”.

“In terms of behaviour patterns, goldfish were also found to be much braver, a trait linked with invasive spread,” the study says.

Lead author Dr James Dickey from the QUB School of Biological Sciences said the research “suggests 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,” he said.

“Our research highlights that goldfish are high risk, but we hope that the methods developed here can be used to assess others in the pet trade across Ireland and further afield,” Dr Dickey said.

“Readily available species are most likely to be released, so limiting the availability of potentially impactful ones - alongside better education of pet owners - is a solution to preventing damaging invaders establishing in the future,” he said.

The QUB research was funded by the Alexander von Humboldt Foundation, Inland Fisheries Ireland and the Northern Ireland Department of Agriculture, Environment and Rural Affairs (DAERA)

The findings were presented at the International Conference on Aquatic Invasive Species in Oostende, Belgium along with a range of other leading research from QUB on alien species.