Hatchetfishes are mesopelagic fishes which are laterally compressed. They have photophores on their ventral surfaces to eliminate their silhouette from predators looking upward from below. This "hide in plain sight tactic is known as counterillumination. The Highlight Hatchetfish (Sternoptyx pseudobscura) can be found to depths of 2,000 meters. This individual was captured in a trawl between 1,200 and 1,000 meters depth in the Gulf of Mexico, 2016. Image courtesy of the DEEPEND project.