Salvelinus fontinalis agassizii The silver trout (Salvelinus agassizii) is an extinct char species or subspecies that inhabited a few waters in New Hampshire in the United States prior to 1939, when a biological survey conducted on the Connecticut watershed by the New Hampshire Fish and Game Department found none.

[3] To formally describe the species and prevent local fishermen from overharvesting in the absence of bag limits, specimens were sent to Harvard and the U.S. National Museum for identification, where the fish was first described as a form of lake trout (Salvelinus namaycush), and later as a variety of brook trout (Salvelinus fontinalis) by Spencer Fullerton Baird.

[3] The silver trout was described as Salmo agassizii by Samuel Garman in 1885, honoring Agassiz for his early identification of the fish.

The silver trout inhabited the deeper reaches in the center of Dublin/Monadnock Pond for most of the year, migrating to the shallows to spawn during the fall.

[6] The silver trout had already been significantly diminished in Dublin Pond by 1874, with claims of much larger populations in the past.

[3] By the late 19th century, as each lake developed its own steady summer tourism, recreational fishermen who sought to increase their catches began to introduce new fish species, and these eventually overwhelmed the native silver trout.

However, potential later records exist of a number of alleged silver trout specimens caught throughout the 1930s, which were documented by John E. Coffin in the January 1939 issue of Outdoor Life.