Atlantic Black Durgon Triggerfish (Melichthys niger)

Most triggerfish stake out a patch of reef and defend it alone; the Black Durgon breaks ranks and schools by the dozens in open water along drop-offs, picking plankton out of the current like it forgot it's a trigger. It still carries the family's signature defense — a dorsal spine that locks upright and wedges the fish into a crevice so hard that predators, and more than one frustrated aquarist, give up trying to pull it loose. Quick learners that recognize their keeper on sight, with jet-black bodies that flash blue-green under the right light.

Care level: Moderate · Temperament: Aggressive · Max size: ~12" · Min tank: 125+ gal · Diet: Carnivore, meaty foods