The Patagonian blennie was first formally described in 1830 as Eleginus maclovinus by the French zoologist Georges Cuvier with the type locality given as the Falkland Islands.

[7] The Patagonian blennie is found in the southeastern Pacific and southwestern Atlantic Ocean from Valparaiso in Chile south to Tierra del Fuego and north along the coast of Patagonia in Argentina,[8][7] It is also found around the Falkland Islands.

In some parts of its range, it is especially fond of Paracorophium,[9] but it is opportunistic, and its exact diet depends on the availability in the habitat where the individual fish lives.

[10] There have been trials for the use of this species as a cleaner fish to control sea lice in the aquaculture of salmonids in Chile.

[9] The abundant and nutritious patagonian blennies were apparently not consumed by the indigenous people of Tierra del Fuego.