The silver trout (Salvelinus agassizi) is an extinct trout species last seen in Dublin Pond, New Hampshire, in 1930, in a catch of six. The only properly confirmed occurrence of the fish was also in Dublin Pond.
The silver trout was often a foot long and was said to actually be olive green in color. It was an exceedingly rare fish, having become trapped (by changed drainage systems) in three New Hampshire lakes (Dublin Pond, Sunapee Lake, and Christine Lake in Stark) that were left as isolated pockets by a retreating glacial front approximately 8,000 years before, following the end of the last Ice Age. In the deep waters of these lakes, cut off from other species, the silver trout had no natural predators.
However, by the late 19th century, as each area developed its own steady summer tourism, recreational fishermen who sought to increase their catches began to introduce new fish species into these lakes, and these eventually overwhelmed the native silver trout. Yellow perch, which eat trout eggs, were particularly devastating. Very small numbers of silver trout may have survived into the 1950s and 1960s, but they are extinct today.