Octopus, fish, echinoids, worms, squid and mollusks live in the abyssal zone, which begins at about 13,000 feet below sea level. Most of the organisms there have small bones, soft bodies, big mouths and long teeth. Few animals have what it takes to survive this freezing zone with no light.
Basketstars and anglerfish can be found in the abyssal zone. Abyssal fish typically live longer and reproduce more slowly, and most of them are small. The creatures that live in the abyssal zone are from the same groups as those that live in shallower depths of the ocean, but the difference is that the abyssal organisms evolved specializations that allow them to live in this unique environment, including under the extreme pressure caused by the weight of water at that depth. In addition, some abyssal fish have stretchable stomachs that allow them to eat a meal bigger than they are, because they might not get another meal for quite some time.
The abyssal, or abyssopelagic, zone ranges from 13,124 feet to 19,686 feet. Because no light penetrates lower than approximately 600 feet, the energy source for creatures in the abyssal zone primarily comes from the organic matter that sinks down from shallower depths.