Danionella priapus

Danionella priapus is the 4th species to be named and made scientifically known in a genus of miniature and highly developmentally-truncated carp-like fishes. It is new to science, having been described scientifically for the first time in a paper published in Zootaxa in October 2009.

The genus Danionella includes some of the world's smallest fishes and vertebrates.

Species detail

With a maximum length of 16mm, D. priapus is one of the larger species in the genus Danionella. 

When alive these fish are almost completely translucent with only:

  • a few rows of melanophores
  • a thin yellowish-greenish line running along the body at the level of the neural tube (the fish's central nervous system)
  • golden chromatophores forming a ring around the pupil and capping the swimbladder chambers and their connecting duct
  • Danionella priapus specimens demonstrating difference in pelvic-fin structure
    Taxonomy

    Find out about the characteristics of this minature fish and how it can be readily distinguished from other species in the same genus.

  • Living female specimen of Danionella priapus
    Biology and behaviour

    Information about the biology and behaviour of any of the Danionella species is largely lacking. Find out what is known about D. priapus.

  • Jorai River
    Distribution and conservation

    So far, this miniature fish has only been collected from the Jorai River in India. Due to the species' very recent scientific discovery, its conservation status cannot be properly assessed. Learn more.

  • Head of Danionella priapus
    References

    Get reference material about the 4 Danionella species.

Images

Live Danionella priapus male and female fish

Colouration of live Danionella priapus male (top) and female (bottom). (Images: Ralf Britz, Natural History Museum)

A view of the Jorai River at Laskapara in India

A view of the Jorai River at Laskapara in India, where Danionella priapus has been found. © Peter Cottle

Lateral view of Danionella priapus specimens

Lateral view of Danionella priapus male (top) and female (bottom). (Images: Ralf Britz, Natural History Museum)

Dorsal view of the colour pattern of Danionella priapus head and anterior body

Dorsal view of the colour pattern of the head and anterior body of a male specimen of Danionella priapus. (Image: Ralf Britz, Natural History Museum)

Male Danionella priapus showing pelvic fins and genital papilla

Close-up of the modified pelvic fins and conically-projecting genital papilla (tube that sperm is released through) of a male Danionella priapus. (Image: Ralf Britz, Natural History Museum)

About the author

Ralf Britz
Dr Ralf Britz

Researcher in the Zoology Fish Research Group who has discovered numerous fishes and named a total of 40 new freshwater fish species, including Danionella dracula.

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Glossary

Chromatophores
Pigment-containing cells.

Melanophores
Chromatophores in which the pigment is melanin.