Out-of-place creature found in pond in London for first time in 50 years. See it
While surveying a pond in London, United Kingdom, a fishery employee found an out-of-place creature with a “rosy” hue. Scientists later identified it as a popular aquarium pet and the country’s first record of the species in 50 years.
Keith Wesley with Bedwell Fisheries Services visited Golders Hill Park in October 2021 as part of a “fish survey in northwest London,”according to a study published Sept. 1 in the peer-reviewed Journal of Fish Biology.
While there, Wesley caught a pink fish from a pond at the western edge of the park. He “recognised its importance” and sent the fish to scientists, the study said.
Researchers identified the fish as a rosy barb and the first “wild-caught” example of the species “in the UK since the 1970s.” A photo shows the roughly 2.5-inch fish.
The rosy barb, or Pethia conchonius, is a “small” fish species “native to lakes and streams in subtropical regions of southern Asia,” the study said. The species is “widely traded worldwide as an ornamental fish due to its attractive colouring and ease of breeding in captivity.”
Researchers suspect the rosy barb found in London was “most likely released from an aquarium,” especially since the pond was “within 10 m (about 30 feet) of a potential car parking site and access gate into the park.”
“Accidental or intentional release of (non-native species) into the wild can introduce both the species themselves and any pathogens they carry, jeopardising native wildlife,” the study said. Under UK law, “any release of non-native fish from aquaria into the natural environment is prohibited.”
The rosy barb “is currently unlikely to establish” an invasive population in the UK “due to limiting temperatures” but climate change induced temperatures and a “sustained warm environment” could change that, researchers said.
“This finding underscores the need to reduce further releases of exotic species from the pet trade, particularly in areas at high risk of introductions due to their accessibility,” the study said. “Even seemingly innocuous species such as P. conchonius (rosy barbs) can pose a potential risk.”
Golders Hill Park is in northwestern London and a roughly 5-mile drive from the city center.
The research team included Peter Barry, Phil Davison, Luke Pearson and Gordon Copp.
This story was originally published September 2, 2025 at 9:04 AM with the headline "Out-of-place creature found in pond in London for first time in 50 years. See it."
