Rangers at St. Vrain State Park estimate 30,000 fish perished in a die-off earlier this month at Sandpiper Pond. About a quarter of the fish were cleaned up and the rest were left for wildlife.
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The number of dead fish seems staggering, but Kara Van Hoose with Colorado Parks and Wildlife said you have to keep it in perspective.
"When you look at it in a bigger picture, if we stock, you know, 6,000 fish of one species and then 7,000 of another in there, and then there's natural reproduction, like really hundreds of thousands of fish can survive in one smaller water body," Van Hoose said.
The fish died because oxygen levels dropped in Sandpiper Pond. When water temperatures get hot, oxygen disappears, leaving fish vulnerable to die-offs.
"Die-offs unfortunately happen, especially in really hot summers and summers where we don't have a lot of water," said Van Hoose.
CPW said the fish population at St. Vrain State Park remains healthy.
Rangers at the park left most of the dead fish for wildlife. Birds, coyotes, raccoons, and other mammals will scavenge the carcasses.
This year's drought is forcing managers at the park to change their fish stocking plans for the fall. Van Hoose said Sandpiper and other north ponds won't be restocked due to low water levels.
"We take a look at if there's going to be water available and what kind of levels we'll most likely have later on in the year, and then kind of adjust from there. So we made that decision because it just wasn't going to be sustainable for the fish population," she said.
CPW has been busy this summer trying to prevent fish die-offs because of the ongoing drought. An emergency fish salvage order went out this week for Banner Lakes State Wildlife Area in Weld County. Another fish salvage is ongoing at McKay Lake in Westminster.
