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Idaho Fish and Game


Fish and Game treats Heagle Pond in Hailey killing thousands of invasive goldfish


Invasive goldfish, fathead minnows, koi and perch were killed in a rotenone treatment of Heagle Pond in Hailey, ID following illegal dumping of the fish into the Heagle Park pond.

In the spring of 2020 Fish and Game received reports of goldfish swimming in Heagle Pond adjacent to Lawrence Heagle Park in Hailey. This week, fisheries biologists with Fish and Game treated Heagle Pond with rotenone, a natural plant-based substance that is toxic to fish. Immediately following the rotenone, thousands of goldfish and other fish species were collected from the pond. The rotenone will degrade naturally over the next few weeks. The pond, which currently is fenced off and signed to keep people and pets safe, will continue to be monitored by Fish and Game and any additional dead fish will be collected and disposed of at a certified disposal facility.


Fish and Game biologists apply rotenone to Heagle Pond in Hailey

Goldfish are a member of the carp family, which have never been documented in the Wood River Basin.

“The illegal introduction of invasive species into Idaho’s waters is an extremely concerning situation” said Mike Peterson, Regional Fisheries Manager, “what we found today is that the goldfish that were illegally introduced into Heagle Pond were successfully spawning, which could put the fisheries in the Big Wood River at risk.”

Within minutes of the rotenone application biologists found thousands of small goldfish, and fewer numbers of Koi and rainbow trout. A perch was also found in the pond which is a fish species that does not belong in Wood River Valley ponds. According to biologists, finding a perch is Heagle Pond is a perfect example of a deliberate action by someone who illegally transported a live fish and put it into Heagle Pond.


Goldfish and fathead minnows collected following the rotenone treatment

“Illegal introductions and the necessary actions to remove the invasive species take money away from regional fisheries projects” said Joe Thiessen, Regional Fisheries Biologist, “we had to divert limited license dollars to deal with a situation that was caused by someone dumping their pet goldfish into Heagle Pond.”


Goldfish removed from Heagle Pond in Hailey following a rotenone treadment

In Idaho, anglers or aquarium owner’s illegally transplanting or introducing fish where they don’t belong can be held legally responsible for the financial costs to restore the fishery to its prior condition. Restoration efforts could potentially total in the hundreds of thousands of dollars! The illegal act of introducing fish into another waterbody can potentially result in a felony charge.

Despite good intentions, residents dumping any aquarium fish into streams, rivers or ponds can have serious ecological impacts to our public waterways. Illegally introduced fish, like goldfish, can be extremely hardy and both survive and reproduce in the wild. It’s everyone’s responsibility to keep Idaho’s waterways and ponds free from invasive species.

For more information, contact the Magic Valley Region at (208) 324-4359.