SCIENTIFIC NAME: Hiodon tergisus
CHARACTERISTICS: The mooneye is an elongate fish with a short head and a large, silvery eye covered with an adipose eyelid. The dorsal fin origin is distinctly anterior to the anal fin origin. The dorsal fin has 11 or 12 rays; the anal fin, 26 to 29 rays (fewer than the goldeye). The fleshy keel along the venter extends from the pelvic fin base to the anus. The upper jaw extends almost to the middle of the pupil. In live individuals the back varies from bluish green to silvery, and the sides and venter are glossy and silvery. See Lesueur (1818a) for original description.
ADULT SIZE: 12 to 18 in (300 to 460 mm)
DISTRIBUTION: The mooneye is an elusive species, and because it appears only infrequently in collections, its distribution in Alabama is incompletely known. Previous reports stated that mooneye had not been collected in the Tennessee River drainage since 1938 and 1941. However, we collected them at five stations in 1993: two in the Elk River, two in the Paint Rock River (where the species was fairly abundant), and one in Shoal Creek. Biologists with the Tennessee Valley Authority reported mooneye from the Elk River in 1980 and the Tennessee River drainage 1962 and 1976. Jandebeur (1972) collected a single specimen with a trammel net in the lower Elk River in 1968. We have collected mooneye in the Alabama, Cahaba, Coosa, and Tallapoosa river systems below the Fall Line in the Mobile basin.
HABITAT AND BIOLOGY: Mooneyes are surface feeders in large streams and rivers. They thrive in greatest abundance in the swift tailwaters of locks and dams. Spawning occurs in March and April, probably in swift water over sand and gravel substrates. Several male and female mooneye in “running ripe” condition were collected in a hoop net from Bull Mountain Creek, a tributary to the upper Tombigbee River in northeastern Mississippi, in May. Females of this species do not have oviducts, meaning that eggs are released directly into the body cavity before spawning. Etnier and Starnes (1993) report that mooneye grow rapidly in Tennessee, with year-old fishes reaching 8 inches (200 mm).
ORIGINAL DESCRIPTION: Lesueur described the mooneye in 1818.
Hiodon means tongue tooth, referring to the tiny teeth on the tongue.
Tergisus means polished.
The copyrighted information above is from Fishes of Alabama and the Mobile Basin.