noun, plural (especially collectively) black·fish, (especially referring to two or more kinds or species) black·fish·es.
Examples from the Web for blackfish
To this day, multiple SeaWorld employees who have seen the film suggest to me that Blackfish barely scratches the surface.‘Blackfish’ Director: Killer Whales Don’t Belong in Captivity|Gabriela Cowperthwaite|October 24, 2013|DAILY BEAST
Mike Barnett of Freeport, Long Island is busy catching striped bass and blackfish.
Furthermore, false killer whales are the only "blackfish" which are known to ride the bow wave of a ship.Whales, Dolphins, and Porpoises of the Western North Atlantic|Stephen Leatherwood
Dolphins, rock-cod, pigfish, and blackfish may be caught as quickly as they can be hauled out.Real Soldiers of Fortune|Richard Harding Davis
The relative size of a blackfish and a man is shown at Fig. 3.Friction, Lubrication and the Lubricants in Horology|William T. Lewis
But it was neither a whale nor a blackfish—not even a small one—nor was it a shark.Creatures of the Abyss|Murray Leinster
Through binoculars he made out a shape under the water, too large to be a blackfish, lying diagonally across the K's course.