Hiodon tergisus LeSueur, 1818

member of the Mooneye Family (Hiodontidae)













What's In a Name?
Mooneye: taken from the pale color of the eye

Hiodon (hi-oh-don´) means "toothed hyoid" in Greek, referring to the "tongue" bone
tergisus (ter-gee´-suss) means "polished" in Greek; taken from the shinny look of the fish


    Where Do They Live?
The mooneye is present in all of Minnesota's major drainages, except for the upper Mississippi River and Lake Superior drainage systems. Like the goldeye, this fish prefers the quiet areas of large rivers and their connected lakes and marshy backwaters. It occurs in turbid (cloudy) waters but is less tolerant of these waters than the goldeye is.


How Big Do They Get?
How Long Do They Live?
In Minnesota, mooneyes typically reach 250-300 mm (10 -12 in) in length and weigh about 280-350 g (about 8-10 oz). The record in Minnesota for this fish is 0.88 kg (1 lbs 15 oz). It was caught in the Minnesota River in Redwood County. Mooneyes frequently live to 6 years old, but occasionally may reach 8-10 years old. On average, females live longer than males do.

    What Do They Eat?
Young mooneyes eat copepods, waterfleas, and small insect larvae. Adult mooneyes mostly eat a variety of terrestrial (land) and aquatic (water) insects, especially mayflies and caddisflies. They also eat a variety of small fishes (mostly minnows).

What Eats Them?
Mooneyes are probably eaten by the same fish predators as goldeyes. These include northern pike, sauger, and walleye. Although they are less sought after than goldeye, they are still taken by a few commercial operations in Minnesota and Wisconsin.


How Do They Reproduce?
Unfortunately, very little is known about the spawning habits of mooneye. Mooneyes probably begin spawning at about the same ages as the goldeye and their spawning season is similar (late April to June). Unlike goldeyes, mooneyes tend to migrate into clearer streams, where they spawn in moving water. They probably broadcast their eggs on gravel and pebble substrates. A single female can release 10,000-20,000 eggs, depending on her size.


Conservation and Management
Mooneyes have been a minor commercial species, sometimes being used when the goldeye catch was small. They are occasionally caught by anglers, but more by accident then by intention.




Permission is granted for the non-commercial educational or scientific use of the text and images on this Web document. Please credit the author or authors listed below.

Photographs by Konrad P. Schmidt
Text by Nicole Paulson & Jay T. Hatch in cooperation with
the Minnesota Department of Natural Resources' MinnAqua Aquatic Program

This page developed with funds from the
MinnAqua Program
(Minnesota Department of Natural Resources, Division of Fisheries)
and the
Sport Fish Restoration Program (Fish and Wildlife Service, US Department of the Interior)

Maintained by Jay T. Hatch
General College and James Ford Bell Museum of Natural History
University of Minnesota, Minneapolis/St. Paul

Last updated 28 January 2002