Federal park officials in San Francisco are building an “amnesty pond” for unwanted pet fish — to help keep a beautiful lake free of nonnative fish.

Mountain Lake, on the southern border of the Presidio park, was recently poisoned to kill off invasive species, claiming catfish, bass and more than 850 carp, SFGate reported.

But the Presidio Trust does not want another purge to kill so many fish again, so the group thought of a way to prevent them from showing up in Mountain Lake in the first place.

The problem arose because pet owners had been releasing their unwanted fish in the lake’s waters.

“The presence of these and other invasive fish in the lake prevents the successful reintroduction of native species and overall restoration of the lake,” reads a message on the group’s site.

So the fish were killed with CFT Legumine, a botanical fish toxicant with rotenone as its active ingredient.

That’s why the Presidio Trust is building an amnesty pond near the lake to give fish dumpers another option, according to SFGate.

Meanwhile, Mountain Lake will be repopulated with creatures native to the area, such as the western pond turtle, the California floater mussel and the three-spined stickleback.

The lake will be monitored to make sure the rotenone has completely degraded before restoring the fish.

The Presidio Trust is spending $12 million to restore the lake, according to reports.





