Some of the oldest bony fish live in the cold, dark deepwater. One of these is the black oreo (Allocyttus niger) shown here (from a 33cm, 795g male). The image on the right shows a whole otolith and the white line indicates where the otolith is sliced through. The sliced surface, when examined under a microscope, reveals a series of growth lines. This example indicates that this fish was about 60 years old. Credit: Caoimhghin Ó Maolagáin
