Mooneyes and Goldeyes: Order Hiodontiformes

A new order for two unique North American fish

The order Hiodontiformes consists of only two fish, the mooneye (Hiodon tergisus) and the goldeye (Hiodon alosoides). Both fish were previously grouped together in the order Osteoglossiformes, until it was determined that the two broke off quite early in evolutionary history, warranting a new group. If you read the text of older books, you'll notice that this group just doesn't exist.

Mooneye - Hiodon tergisus

The mooneye is a medium sized freshwater fish (up to 45 centimeters) popular with game fishermen in certain areas of North America. While never common it is listed as either critically imperiled in NY, NC, GA, MI, IL and PA.

Mooneyes are found in the following areas in the US. Note that they are most common in Manitoba and other Canadian provinces.

Mooneyes are found in freshwater habitats in medium to large rivers and lakes. They prefer deep pools and backwaters with clear water. While they are often found in still waters, they prefer to feed in swift moving water. Mooneyes reproduce in the spring by spawning. Most mooneyes will migrate upriver to do their spawning. Mooneyes feed on aquatic and terrestrial insects, crustaceans, molluscs, and small fishes.

Goldeye - Hiodon alosoides

The goldeye is a slightly more bronze colored version of the mooneye reaching similar sizes (up to 50 cm). Just like mooneyes, they migrate upstream in the spring to spawn in shallow streams and then back downstream in the fall. They overwinter in deep quite water.

Goldeyes feed on aquatic insects obtained at the surface of the water. They will also eat other animals like frogs and small mammals. Young goldeyes feed on microcrustaceans and other invertebrates. The following map shows the US distribution of goldeyes. Note that goldeyes are also common in freshwater drainages in all the Canadian provinces bordering the US.