Sunday, 25 September 2011

Sloane's viperfish

Image of a Sloane's viperfish
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Stomiiformes
Family: Stomiidae
Genus: Chauliodus
Species: Chauliodus sloani
Common Names: Sloane’s viperfish, Sloane’s fangfish

Despite its frightening appearance, the Sloane's viperfish (or Sloane’s fangfish) is a harmless to humans dragon fish of the Chauliodus genus. It can be found all over the world in tropical and subtropical oceans, living in very deep depths.

They are bathypelagic animals that live only for a few hours in captivity, as a result we don't know much about them.

Sloane's viperfish Description
Sloane's viperfish is a species of Viperfish, reaching a total length varying from 20 to 35 cm (8-14 inches) with a 2 cm long head (0.8 inches). They come in a variety of colors including shades of:
  • Blue
  • Green
  • Black
  • Silver

The fish is best known for having the Guinness record for largest teeth in comparison to its head-size, among all known species of fish. The teeth are so big that the Sloane’s viperfish has to open its jaws almost vertically before swallowing its prey.

Like all species of viperfish, the Sloane’s fangfish has photophores. These are small organs in their dorsal spine used both for hunting and communication (with potential mates or rivals.) These light-producing organs flash on and off luring all kinds of prey. They stay totally still while hunting. Once pray comes close enough they will first snap it using their huge teeth and then swallow it.

Sloane’s fangfish engage in what is known as asynchronous diel vertical migration. This means that they vertically migrate in higher depths during the night, probably to increase their chances of finding prey.

In the wild, these fishes are believed to have a life span of 20-30 years. However, caught specimens only survive for a maximum of 12-18 hours.

Sloane's viperfish habitat
They are bathypelagic fishes, living in depths starting from 400 up to 2800 meters (1310 to 9185 ft). Their habitat includes all the oceans belonging to temperate and tropical zones with their range extending from 63 ° N to 50 ° S.

Sloane's viperfish Diet
They are carnivorous animals with a relatively low basal metabolic rate. This is an adaptation to the low amounts of available food supplies that characterizes their habitat. It is believed that they can survive just by eating once every ten days!
Sloane's viperfish are known to feed on:
  • Small crustaceans
  • Small fishes

They are even capable of hunting and swallowing fish that are 63 % of their own body length!

Sloane's viperfish predators
Chauliodus sloani has many natural bathypelagic and mesopelagic predators. These are its currently known predators:
  • Spinner dolphins (Stenella longirostris)
  • Common dolphin fish (Coryphaena hippurus)
  • Fraser's dolphins (Lagenodelphis hosei)
  • Coster dories (Allocyttus verrucosus)
  • Black mouth cat sharks (Galeus melastomus)
  • Portuguese dog fish (Centroscymnus coelolepis)
  • Orange roughy (Hoplostethus atlanticus)
Due to its size, this viperfish can't directly defend itself against predation. Its only mean of protection is the lack of light characterizing its habitat combined with the Sloane's natural dark coloring.

Sloane's viperfish reproduction
Little is known regarding their reproduction, however according to a few reports they are oviparous, spawning their eggs externally once per year. In other words females release eggs into the water and afterwards the males release their egg- fertilizing sperm.

Sloane's viperfish Conservation Status
Due to its bathypelagic nature, the Sloane’s fangfish isn't a well studied animal and as a result we don't know much about its current population. As of this moment, it is not in the IUCN Red List, however we really don't know if it is actually threatened or not by anything. Nevertheless, it is believed that human activity has very little (if any) impact on this fish.

References & Further Reading
- Mari Butler, Stephen M Bollens, Brenda Burkhalter, Laurence P Madin, Erich Horgan (2001). Mesopelagic fishes of the Arabian Sea: distribution, abundance and diet of Chauliodus pammelas, Chauliodus sloani, Stomias affinis, and Stomias nebulosus Deep Sea Research Part II: Topical Studies in Oceanography DOI: 10.1016/S0967-0645(00)00143-0
- Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand, (William Collins Publishers Ltd, Auckland, New Zealand 1982) ISBN 0-00-216987-8


  1. Freaky! It looks like a rotting corpse!

  2. Good blog, but you have quite a few typos. The common dolphin is a mammal and not a fish. But I'm sure that you are aware of that. Otherwise, this is a very helpful read. :)