Dracula minnow (Danionella dracula)

What’s the World’s Favourite Species?

Dracula minnow fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Dracula minnow description

First described as a new species as recently as 2009 ⁽¹⁾, the Dracula minnow is a tiny freshwater fish named for the impressive, tooth-like ‘fangs’ of the male. The males of this miniature fish possess a series of long, pointed, tooth-like structures in the jaw, formed from bone, with those at the front of the mouth being elongated into long, canine-like fangs. This feature is unique among the 3,700 or so species of cyprinid fish (species in the order Cypriniformes), which all lack true teeth ^{(1) (3)}.

The genus Danionella includes some of the world’s smallest fish species, and despite being the largest member of its genus ⁽³⁾ the Dracula minnow only reaches up to about 1.7 centimetres in standard length ⁽¹⁾. These species are also unusual in that even when adult, they retain a larval-like body form and skeleton. For example, compared to other closely related fish the Dracula minnow lacks over 40 bones. This is believed to have occurred through a process known as ‘developmental truncation’, whereby the Dracula minnow does not undergo the last stages of normal development, although it still reaches sexual maturity ^{(1) (4)}.

The Dracula minnow has an elongate body, a large head and large eyes. Its small dorsal fin is situated quite far down the body, above the long anal fin, and it has a forked tail ⁽¹⁾. This unusual fish is largely transparent, apart from five rows of pigmented cells along its body, pigmented cells on the upper surface of its swim bladder, and a thin yellow line running along its side ^{(1) (3)}.

Unlike the male Dracula minnow, the female only has rudimentary tooth-like structures ^{(1) (4)}, and also differs in having much smaller pelvic fins ⁽⁴⁾. The Dracula minnow can be distinguished from other members of its genus by the male’s distinctive ‘fangs’ ^{(1) (3)}.

Also known as

Dracula fish.

Size

Length: 13.1 - 16.7 mm ⁽¹⁾

Dracula minnow biology

Very little is currently known about the biology of this newly discovered fish ^{(2) (3)}. However, it is thought that the male Dracula minnow’s unusual ‘fangs’ may be used in fighting, as males in captivity have been observed opening their jaws widely and jostling each other ⁽⁵⁾.

Dracula minnow range

The Dracula minnow is so far known only from the place where it was first collected, in a small stream near Sha Du Zup on the upper Irrawaddy River drainage, in northern Myanmar ^{(1) (2) (3)}.

Dracula minnow habitat

The Dracula minnow has been collected from small, well-oxygenated, fast-flowing mountain streams ⁽²⁾.

Dracula minnow status

The Dracula minnow is classified as Data Deficient (DD) on the IUCN Red List ⁽²⁾.

Dracula minnow threats

As information on the Dracula minnow is currently lacking, its conservation status cannot yet be properly assessed ^{(2) (3)}. This miniature fish has so far only been found in a single location, and little is known about its distribution, population size or potential threats. The general threats to the area in which it is found are also not well understood ⁽²⁾.

The Dracula minnow has been reported to be occasionally exported for the ornamental fish trade, but without further information on its wild population the potential impacts of this are unknown ⁽³⁾.

Dracula minnow conservation

There are no specific conservation measures currently known to be in place for the Dracula minnow. Further research is needed into the distribution, populations and biology of this intriguing species, as well as into the threats it may face, before its conservation status can be properly assessed and any appropriate actions taken to protect it ⁽²⁾.

Find out more

Find out more about the Dracula minnow:

• FishBase - Danionella dracula:
  http://www.fishbase.org/summary/Danionella-dracula.html
• Natural History Museum - Danionella dracula:
  http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/collecting/danionella-dracula/index.html

Find out more about newly discovered species:

• ARKive - Newly Discovered species:
  http://www.arkive.org/newly-discovered-species/

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Anal fin

In fish, an unpaired fin on the under surface of a fish, behind the anus.

Dorsal fin

The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans (whales, dolphins and porpoises).

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Larval

Of or relating to the immature stage in an animal’s lifecycle, after it hatches from an egg and before it changes into the adult form. Larvae are typically very different in appearance to adults; they are able to feed and move around but are usually unable to reproduce.

Order

A category used in taxonomy, which is below ‘class’ and above ‘family’. All members of an order have characteristics in common.

Pelvic fins

In fish, the pair of fins found on the underside of the body.

Standard length

In fish, the length from the snout to the base of its tail (caudal) fin.

Swim bladder

Also known as a gas bladder, an air-filled sac inside the body of many fish which is used to control buoyancy.

References

1. Britz, R., Conway, K.W. and Rüber, L. (2009) Spectacular morphological novelty in a miniature cyprinid fish, Danionella dracula n. sp. Proceedings of the Royal Society B - Biological Sciences, 276: 2179-2186. Available at:
   http://rspb.royalsocietypublishing.org/content/276/1665/2179.full.pdf+html
2. IUCN Red List (February, 2013)
   http://www.iucnredlist.org/
3. Natural History Museum - Danionella dracula (February, 2013)
   http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/collecting/danionella-dracula/index.html
4. Natural History Museum (2009) Dracula minnow has teeth, almost. Natural History Museum News, 11 March. Available at:
   http://www.nhm.ac.uk/about-us/news/2009/march/dracula-minnow-has-teeth-almost28552.html
5. Black, R. (2009) ‘Dracula’ fish shows baby teeth. BBC News, 11 March. Available at:
   http://news.bbc.co.uk/1/hi/sci/tech/7935482.stm