Dolly Varden
noun
Dol·ly Var·den ˌdä-lē-ˈvär-dᵊn- 
variants or Dolly Varden trout
: a large freshwater or anadromous char (Salvelinus malma) that is widespread in streams of northwestern North America and eastern Asia, may attain a weight of 20 pounds (9.1 kilograms) but is usually much smaller, and is typically olive green to greenish-brown with yellow to red spots when found in fresh water and silvery with orange spots in salt water
Word History
Etymology
Dolly Varden, gaily dressed coquette in Barnaby Rudge (1841), novel by Charles Dickens
First Known Use
circa 1876, in the meaning defined above