When owners decide to set their goldfish free of the confines of the fish bowl, they could be letting loose what researchers call an ecological catastrophe for native biodiversity. Biologists in North Ireland looked at the effects of releasing two popular pet fish species: goldfish (Carassius auratus) and the white cloud mountain minnow (Tanichthys albonubes). Goldfish, they found, were far more harmful. “Our research suggests that goldfish pose a triple threat,” said James Dickey, a professor at Queen’s University Belfast and the lead author of the study published in NeoBiota. “Not only are they readily available, but they combine insatiable appetites with bold behavior. 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.”
The team hopes their method can be used to assess the risk of other species released from the pet trade.