Pet goldfish released into the wild are becoming killing machines.

Pet goldfish are becoming killing machines

Pet goldfish are becoming killing machines

The fish are wreaking havoc on native species and are threatening biodiversity by outcompeting rivals.

The goldfish contribute to poor water quality by uprooting plants and messing up bottom sediments and researchers fear that they could have disastrous consequences for the planet.

Dr. James Dickey, from Queen's University Belfast, said: "Our research suggests goldfish pose a triple threat. Not only are they readily available but they combine insatiable appetites with bold behaviour.

"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.

"They could pose a real threat to native biodiversity in rivers and lakes, eating up the resources that other species depend on."