"Inconnu" is the French word for "unrecognized" or "unknown." It is occasionally used to mean a unknown person in English, but its most common English meaning is a species of fish. They were named by French-Canadians accompanying Alexander Mackenzie on his 1789 attempt to find a Northwest Passage for ships. The voyageurs found an unfamiliar fish and started calling it "poisson inconnu."

The inconnu (Stenodus leucichthys), sometimes nicknamed "connie" or "coney," and also called sheefish, resembles a salt-water tarpon or a large herring, and is the largest member of the whitefish family. They live in Arctic and sub-Arctic areas of Alaska, Canada and Siberia, usually in large, muddy rivers and lakes. They are predators who eat other fish, shrimp, and insects. In size, they average about 4 to 9 kg (9 to 20 lbs.) and are occasionally caught by fishermen. Its oily flesh works well as smoked fish.

Inconnu is also the name of a "folk-roots-rock" band from Whitehorse in the Yukon, made up of Lucie Desaulniers-Andrieu (vocals), Nick de Graff (guitar & vocals), Andrea McColeman, (keyboards, accordion, percussion, & harmony vocals), Jay Burr (tuba), and Marc Paradis, (drums). Their music has been described as a fusion of cajun, blues and jazz for a "distinctive Canadian sound." They perform songs in both English and French, and have two CDs, Inconnu and Back To The Water on Caribou Records.

Sources:
http://wordsmith.org/awad/archives/0602
http://www.bcfisheries.gov.bc.ca/Publications/inconnu.pdf
http://www.nwtwildlife.rwed.gov.nt.ca/fishing/inconnu.htm
http://www.algonet.se/~sjostran/English/10144.htm
http://www.ncr.dfo.ca/zone/underwater_sous-marin/inconnu/unknown.htm
http://www.caribourecords.com/artists/inconnu.html
http://www.coolname.com/go/len_osland