Report a Suspect ANS
If you suspect a new infestation of an invasive plant or animal, save a specimen and complete the following form:
Report a suspected ANS form
How to Prevent Spread
Tench Distribution Map (USGS)

This invasive fish was introduced into Idaho in 1880s and would compete with native cyprinids and game fish in Montana.
The map's red shading shows the Tench's proximity to Montana.
- REMOVE all sediment and vegetation from boats, trailers and equipment.
- WASH all boats, trailers and equipment. High pressure hot water is best.
- DISINFECT equipment with 20% bleach for 10 minutes, 5% bleach for 1 hour.
- DRY all equipment thoroughly.
- DO NOT transfer any water, vegetation or animals between sites (without authorization).