Conventional laboratory studies of deep-sea fish metabolism are not possible as these fish are typically killed during recovery to the surface. As these species are important members of deep-sea communities, the lack of these data represents a significant limitation to our understanding of the functioning of this ecosystem. An autonomous fish respirometer vehicle was developed in order to measure the oxygen consumption of deep-sea fish in situ. This new lander allows measurements to be made without handling or stressing the animals and without the logistical problems and great cost of submersible operations. The design, operation, and measurement methodology are described and preliminary data for Coryphaenoides armatus at 4000m are presented. These Atlantic data appear to confirm the low metabolic rate measured in this species when compared to other gadid species.