"voracious freshwater fish," 1314, probably short for pike-fish, a special use of pike (2) in reference to the fish's long, pointed jaw (cf. Fr. brochet "pike" (fish), from broche "a roasting spit").
Appear, become prominent, as in He was the best writer to come down the pike in a long time. The noun pike here is short for "turnpike" or "road." [Slang; mid-1900s]