Monospecific Families of Freshwater Fishes with no Saltwater Relatives Found in North Carolina

By the Team

There are 12 families of predominantly freshwater fishes that are monospecific (having only one species) in North Carolina (Table 1; Tracy et al. 2020). [Please note: Tracy et al. (2020) may be downloaded for free at:] The Family Xenocyprididae (the single species of Grass Carp, Ctenopharyngodon idella) was previously discussed along with the Cyprinidae (Barbs and Carps) and Leuciscidae (Minnows) ( Some species listed in Table 3 in Tracy et al (2020) might be represented by one species in fresh water, but are more diverse in estuarine or marine waters (e.g., families Engraulidae, Belonidae, Paralichthyidae, and Archiridae) (

FamilyScientific NameAmerican Fisheries Society Accepted Common Name
PolyodontidaePolyodon spathulaPaddlefish
LepisosteidaeLepisosteus osseusLongnose Gar
AmiidaeAmia calvaBowfin
HiodontidaeHiodon tergisusMooneye
AnguillidaeAnguilla rostrataAmerican Eel
CobitidaeMisgurnus anguillicaudatusOriental Weatherfish
LoricariidaePterygoplichthys pardalisAmazon Sailfin Catfish
UmbridaeUmbra pygmaeaEastern Mudminnow
AphredoderidaeAphredoderus sayanusPirate Perch
AmblyopsidaeChologaster cornutaSwampfish
CyprinodontidaeCyprinodon variegatusSheepshead Minnow
GasterosteidaeApeltes quadracusFourspine Stickleback
Aphredoderus sayanus
Pirate Perch – Aphredoderus sayanus

For each of these 12 species information is provided on: 1) its scientific name and American Fisheries Society (AFS)-accepted common name (Page et al. 2013); 2) its common and vernacular names (Smith 1907; Cloutman and Olmsted 1983); 3) the etymology of its scientific name (; 4) unique identifying characteristics; 5) what other species inhabiting fresh water it might be confused with; 6) its distribution within North Carolina; 7) its size; 8) habitats where it can be found; and 9) its imperilment status (where applicable). [Note: see Supplemental Maps 1-3, page 17, showing North Carolina’s 100 counties, 21 river basins, and 4 physiographic regions.]

Hiodon tergisus
Mooneye – Hiodon tergisus – Photograph courtesy of the North American Native Fishes Association

The identification of the monospecific families is not complicated – there are simply few other species with which they could be confused. Some of them are so distinctive, e.g., Longnose Gar, Bowfin, and Swampfish, that it might seem impossible to misidentify them. It is hard to imagine Eastern Mudminnow being mistaken for Bowfin, or Atlantic Needlefish for Longnose Gar, or Bowfin for Northern Snakehead, but it’s been done.

Lepisosteus osseus
Longnose Gar – Lepisosteus osseus – juvenile

If you have troubles with your identifications, just send us ( an e-mail and include as many quality digital photographs as you can along with all the pertinent locality descriptors so that we will know from where the fish came.

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