The grey triggerfish thrives above the rocky bottoms of coastlines, up to 100 m in depth. They tend to be solitary creatures but can also be found in small groups of a few dozen, especially during the mating season.
They are mostly active during the day. They use their small mouths and strong teeth to grind the molluscs and crustaceans that make up their diet.
Their very thick skin is covered with rough scales. This skin forms a stiff membrane that deprives the body of its flexibility. As a result, the grey triggerfish mostly moves around thanks to its dorsal fin.
During the summer, the female burrows a nest in the sand. She cares for her eggs there, while the male guards the area, driving intruders away – even biting them when necessary. When captured, the grey triggerfish makes grunting sounds.
Previously limited to tropical waters, it is now becoming more and more common in cold temperate zones. This change in its range could be due to the warming of cooler waters.
