Hiodon tergisus


Guo-Qing Li and Mark V. H. Wilson
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Containing group: Hiodon


The mooneye, Hiodon tergisus Lesueur, one of only two living species in the genus, is like its sister species found in the fresh waters of the interior of North America, but is perhaps less widely distributed, occurring from Alberta, Saskatchewan, and southern Manitoba and the James Bay lowlands in the north (also in the Great Lakes), to Alabama and Arkansas in the south.

Mooneye usually prefer clear waters of lakes, ponds, and rivers, frequenting shallow habitats. Foods include aquatic invertebrates and small fishes, as well as flying insects that fall in the water and are taken by mooneye at the surface, usually in the evening and at night.

Mooneye live up to 11 years and mature sexually at 3-5 years of age.

Like goldeye they are taken by both sport and commercial fishers but are not of great commercial importance.


Mooneye differs from goldeye in the absence of the fleshy keel in front of pelvic fins (it extends only between the pelvic and anal-fins). The dorsal-fin originates in front of the anal-fin origin, and the mouth extends posteriorly to about the middle of the orbit.

Other characteristics include:

In addition, Hiodon tergisus differs from Hiodon alosoides and †Hiodon consteniorum in the following ratios:

  1. Standard length to body depth ratio about 3.0-3.1 (vs. 3.3-3.4 in Hiodon alosoides and 3.3-3.6 in †Hiodon consteniorum).
  2. Predorsal length to preanal length ratio about  0.92-0.93 (vs. 1.06-1.11 in Hiodon alosoides and 0.83-0.84 in †Hiodon consteniorum).
  3. Anal-fin base length to dorsal-fin base length about 2.0 (vs. 2.74-3.12 in Hiodon alosoides and 1.24-1.35 in †Hiodon consteniorum) (see Li and Wilson, 1994).

Other Names for Hiodon tergisus


Coad, B. W. (1995). Encyclopaedia of Canadian fishes. Canadian Museum of Nature, Ottawa. 928 pp.

Nelson, J. S. (1994). Fishes of the World (3rd edition). John Wiley and Sons, New York. 600 pp.

Nelson, J. S. and M. J. Paetz (1992). The fishes of Alberta (2nd ed.). University of Alberta Press / University of Calgary Press, Edmonton/Calgary. 437 pp.

See the Hiodon page for other references.

Title Illustrations
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Scientific Name Hiodon tergisus
Location Red Deer River near Red Deer, Alberta, Canada
Sex female (top), male (bottom)
Copyright © 1998 Wayne E. Roberts, University of Alberta Museum of Zoology
About This Page

Chinese Academy of Sciences, Beijing , China

University of Alberta, Edmonton, Alberta, Canada

Correspondence regarding this page should be directed to Guo-Qing Li at

All Rights Reserved.

Citing this page:

Li, Guo-Qing and Mark V. H. Wilson. 1998. Hiodon tergisus. Mooneye. Version 01 January 1998. in The Tree of Life Web Project,

edit this page
close box

This page is a Tree of Life Leaf Page.

Each ToL leaf page provides a synopsis of the characteristics of a group of organisms representing a leaf at the tip of the Tree of Life. The major distinction between a leaf and a branch of the Tree of Life is that a leaf cannot generally be further subdivided into subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

close box

Hiodon tergisus

Page Content

articles & notes



Explore Other Groups

random page

  go to the Tree of Life home page