Was the recent discovery of 40-pound invasive fish in Colorado the result of a science experiment?

Fourteen bighead carp culled from an Arvada pond in May 2024 by Colorado Parks and Wildlife officers were stocked in 1992 for a National Biological Service study on reducing nuisance algae.

The fish, native to Asia, were supposed to have been removed but instead grew to more than 3 feet with the largest weighing over 46 pounds. State aquatic biologists said the voracious filter feeders likely did not reproduce but spent the last 32 years growing, fed by zooplankton and algae. No carp were found in neighboring bodies of water.

Without true stomachs the carp eat nonstop and can consume up to 120% of their body weight each day. The species was introduced in the United States in the 1970s to keep aquaculture and wastewater treatment facilities clean. They have since spread to several states, establishing wild but invasive populations.