The black swallower feeds on bony fishes, which are swallowed whole.

Chiasmodon niger (Black swallower)

Black swallowers have been found that had swallowed fish so large that they could not be digested before decomposition set in, and the resulting release of gases forced the swallower to the ocean surface.

The black swallower, Chiasmodon niger, is a species of deep sea fish in the family Chiasmodontidae, notable for its ability to swallow fish larger than itself (for which it is sometimes named the "great swallower").

Along with the giant squid, deep-sea anglerfish and black swallower, it is one of the permanent residents found in the Abyssal zone and was directly observed on the historic voyage of the bathyscaphe Trieste to the Mariana Trench.