The grey triggerfish was first formally described in 1789ny Johann Friedrich Gmelin with its type locality given as the Western North Atlantic, the Indian Ocean and the Mediterranean Sea.

The specific name capriscusis Latin for a "small goat", an allusion Gmelin did not explain, and it is likely to be a mistranslation of its Greek name dating to Aristotle, kápros, which means "boar" or kaprískos.

its diminutive, an allusion to its sharp, powerful and perhaps also to a boar-like ferocity, as described by the Roman author and naturalist Claudius Aelianus in De Natura Animalium, "they fight even with fish of greater bulk and with the most skilled fishermen".

Its native range extends from Nova Scotia to the Caribbean Sea, the Gulf of Mexico and Bermuda, and southwards to Argentina.

[9] Once considered to be an uncommon visitor to northern European seas, an increase in records around the Cornish coast, may indicate it is now breeding there;[10] in addition, it has been found in other areas along the coast of Great Britain in recent years, suggesting that its range is continuing to expand northwards, with one caught as far north as the island of Tiree in the Inner Hebrides, Scotland.

If threatened, the fish can work its way into a protective crevice and wedge itself in place by erecting its front dorsal spine.

An interesting feeding behaviour has been observed, in which the fish positions itself vertically above a sandy seabed and puffs a stream of water out of its mouth.

The fish then adopts its vertical stance once more and attacks the middle with closed jaws, crushing the soft central area.

[8] Males develop a charcoal grey colouration and are highly territorial during the breeding season, which commences in summer when the water temperature reaches about 21 °C (70 °F).

The males prepare up to a dozen nests in hollows blown out of sandy seabed[13] and then patrol the area, driving unwanted fish away.

The fish larvae migrate up towards the surface of the water where they often become part of the community depending on floating sargassum weed.

It is known as a notorious bait stealer and is found over hard bottom in 20 to 40 m (66 to 131 ft) depths off the Atlantic Coast of Florida, often in association with black sea bass and red snapper.