We need YOU to be a pain in the ANS! Excuse me?

We’ll explain. Aquatic Nuisance Species are invasive plants, mussels and other invertebrates that are a growing threat to the waterways within the Roaring Fork Watershed and throughout the state. We need YOUR help to be a pain in the ANS to protect the rivers, lakes, and streams we all love.

October 29, 2025: New Discovery of New Zealand Mudsnails in the Roaring Fork River & Zebra Mussels in the Colorado River 

On October 29, 2025 RFC staff assisted Colorado Parks and Wildlife and 5 other agencies and groups in a different kind of float - looking for zebra mussels and other aquatic nuisance species. This massive effort had over 70 personnel float from the headwaters of the Colorado River in Grand County to Westwater in Utah, and the Eagle, Gunnison, and Roaring Fork Rivers, as well.

The results: Adult zebra mussels were found as far upstream as Glenwood Canyon and for the first time ever, New Zealand Mudsnails were found in the Roaring Fork River.  

Read CPW's press release HERE.

What Can Be Done?

ANS don't move on their own. We the people move them on our gear, boats - anything that was in the infested waterway. Unfortunately, once an ANS species is in a section of river it's just about impossible to eradicate. However, we can slow and prevent their spread. 

After fishing, boating, kayaking, or stand-up paddleboarding CLEAN, DRAIN, and DRY all your gear. Every time. Yes, really, every time. Many ANS are so small they cannot be seen with our eyes and can even survive in damp and moist environments. That’s precisely the time they are transported to a new waterway.

Find out more about the ANS species threatening Colorado, along with tips on how to clean, drain, and dry equipment, watercraft, trailers, and more by visiting Colorado Parks and Wildlife’s ANS webpage at https://cpw.state.co.us/aquaticnuisance-species-program.