Can any fish hold its breath?
Yes. For air-breathing creatures like ourselves, an ability to hold one’s breath is useful should one find oneself submerged. But coffinfish, too, routinely hold their breath in water – for up to four minutes – even though water is what they breathe. As sit-and-wait predators, coffinfish don’t extract oxygen as they swim along. Instead, they must actively inflate and deflate their gill chambers. These chambers are unusually large, allowing the fish to process a large volume of water in one go, which may explain how they can afford to breathe so infrequently. But there could be more to it. Inflation of the gill chambers increases body volume by 30 per cent, which may serve to deter predators, in much the same way that pufferfishes appear bigger by swallowing seawater. Stuart Blackman
Coffinfish respiration – really quite breathtaking.