How do deep-sea fish survive the crushing darkness and pressure?

Deep-sea fish live in conditions with near-total darkness, very little food, and enormous pressure. Their bodies are adapted to avoid damage from pressure, and many have reduced bone density, soft tissues, or jelly-like organs. Some species have large eyes for detecting faint light, while others have no useful eyes at all and instead use smell or touch. Many deep-sea fish also have slow metabolisms, which helps them conserve energy in an environment where meals are rare. Species like anglerfish and gulper eels show just how extreme these adaptations can become.