In 2014, Arizona used fish poison to clear an invasive fish from Virgin River after mechanical removal methods failed. Then the red shiner came back

For years, conservationists waged a relentless battle against the invasive red shiner in the Virgin River. Initial rotenone treatments showed promise, yet the red shiner persistently returned. However, in 2021, a newly designed two-week rotenone treatment method proved effective, allowing the endangered woundfin fish to recolonize their habitat. This ongoing struggle underscores the complexities of eradicating invasive species once and for all.

Raccontata daeconomictimes.indiatimes.com