The Collaborative International Dictionary of English v.0.48:
Bluefish \Blue"fish`\, n. (Zool.)
1. A large voracious fish (Pomatomus saitatrix), of the
family Carangid[ae], valued as a food fish, and widely
distributed on the American coast. On the New Jersey and
Rhode Island coast it is called the horse mackerel, in
Virginia saltwater tailor, or skipjack.
2. A West Indian fish (Platyglossus radiatus), of the
Note: The name is applied locally to other species of fishes;
as the cunner, sea bass, squeteague, etc.