6 Black Swallower Facts: A Fascinating Deep-Sea Creature

The black swallower, scientifically known as Chiasmodon niger, is a unique deep-sea fish that has adapted to living in extreme conditions. This fascinating creature is known for its ability to consume prey much larger than itself, making it a captivating subject for marine biologists and enthusiasts alike. 

In this article, we will explore the basic information, physical characteristics, habitat, diet, reproduction, and conservation status of the black swallower.

1. Basic Information

  • Scientific name: Chiasmodon niger
  • Common name: Black swallower
  • Type of animal: Fish
  • Habitat: Deep-sea environments

The black swallower is a deep-sea fish found in depths of 700–2,745 m (2,297–9,006 ft) below the surface. It’s most commonly found in the North Atlantic. 

2. Physical Characteristics

  • Size: 15 cm to 20 cm
  • Color: brownish-black
  • Distinctive features: Large mouth, expandable stomach

The black swallower is a pretty small fish, usually around 15 cm to 20 cm (maximum recorded length 25 cm). Its color ranges from dark brown to black, allowing it to blend in with the deep-sea environment. The most distinctive features of this fish are its large mouth and expandable stomach, which enable it to consume prey much more significant than itself. 

3. Habitat and Distribution

  • Depth range: 700–2,745 m (2,297–9,006 ft)
  • Oceanic regions: North and south-western Atlantic Ocean
  • Temperature preference: Cold, deep-sea environments

The black swallower inhabits cold, deep-sea environments, typically found at depths ranging from 1700–2,745 meters. The fish is widely distributed and can be found in the tropical and subtropical waters of the northern and southwestern Atlantic oceans. Its preference for cold, deep waters makes it a rare sight for most people, as it is not commonly found in shallow or coastal areas.

4. Diet and Feeding Habits

  • Prey: Bony fish
  • Unique feeding strategy: Swallowing prey whole
  • Stomach capacity: Up to 10 times its own body mass

The black swallower feeds on various bony fish in the deep sea. Its unique feeding strategy involves swallowing its prey whole, allowing it to consume animals much larger than itself. The black swallower’s stomach can expand to accommodate prey up to 10 times its own body mass and twice its length, making it an incredibly efficient predator in its environment.

5. Reproduction and Lifespan

  • Reproductive method: Oviparous (egg-laying)
  • Lifespan: Unknown

The black swallower is an oviparous species, meaning it reproduces by laying eggs. However, little is known about its reproductive habits and the specific details of its life cycle. The lifespan of the black swallower is also unknown, as it is challenging to study this elusive deep-sea creature in its natural habitat.

6. Conservation Status and Threats

  • Conservation status: Data deficient
  • Threats: habitat destruction

Not enough information is available to determine the risk of extinction of the fish. However, like many deep-sea creatures, the black swallower faces threats from human activities such as bycatch and habitat destruction. Continued research and conservation efforts are necessary to protect this unique and fascinating species.


The black swallower is a remarkable deep-sea creature with unique adaptations that allow it to thrive in its extreme environment. Its large mouth, expandable stomach, and ability to consume prey much larger than itself make it a fascinating subject for study. As we continue to learn more about this elusive species, protecting its habitat and ensuring its survival is crucial for future generations to appreciate and study.