noun, plural (especially collectively) jack·fish, (especially referring to two or more kinds or species) jack·fish·es.
Examples from the Web for jackfish
We hear the note of the ruby-crowned kinglet (regulus calendula) which some one says sounds like "Chappie, chappie, jackfish."The New North|Agnes Deans Cameron
These earn a precarious livelihood by fishing for whitefish and jackfish principally in the summer.Hunting in Many Lands|Various
Jackfish proved to be a picturesque hamlet of log huts, clustering on a rocky point of land that jutted into the lake.Gulf and Glacier|Willis Boyd Allen