Topminnow (Family Fundulidae) Diversity in North Carolina

By the Team

The Topminnow Family in North Carolina is a small family of 11 scientifically described and 1 undescribed species (Table 1) occurring primarily within the eastern Coastal Plain and within the estuarine marshes along the Atlantic Coast (Menhinick 1991; Tracy et al. 2020). [Please note: Tracy et al. (2020) may be downloaded for free at:]

Table 1. Species of topminnows found in North Carolina. Common name enclosed within tick marks (“) is a scientifically undescribed species.
Scientific Name/
American Fisheries Society Accepted Common Name
Scientific Name/
American Fisheries Society Accepted Common Name
Golden Topminnow, Fundulus chrysotusStriped Killifish, Fundulus majalis
Marsh Killifish, Fundulus confluentusSpeckled Killifish, Fundulus rathbuni
Banded Killifish, Fundulus diaphanusWaccamaw Killifish, Fundulus waccamensis
Mummichog, Fundulus heteroclitus Fundulus sp. “Lake Phelps” Killifish
Lined Topminnow, Fundulus lineolatusBluefin Killifish, Lucania goodei
Spotfin Killifish, Fundulus luciaeRainwater Killifish, Lucania parva

Often referred to as killifishes, top minnows, or mud-minnows, each species has its own scientific (Latin) name which actually means something (please refer to The Meanings of the Scientific Names of Topminnows, page 13) along with an American Fisheries Society-accepted common name (Page et al. 2013).

Fundulus lineolatus
Lined Topminnow – Fundulus lineolatus male
Fundulus lineolatus
Lined Topminnow – Fundulus lineolatus female

Topminnows range in size from the diminutive Lucania at 50 mm to the 200 mm Striped Killifish. Because of their abundance and the ease by which they can be collected, they are often sold and used as bait fish along the Coast. As previously stated, most species are found in the eastern part of the state, although one species, Speckled Killifish, is found in the central Piedmont (Maps 1- 12). There are no species in our river basins west of the Appalachian Mountains. [Note: see Supplemental Maps 1-3 , page 14, showing North Carolina’s 100 counties, 21 river basins, and 4 physiographic regions.]

Most of our species inhabit a variety of coastal aquatic environments (Table 2) and have a wide-ranging tolerance to salinities. Speckled Killifish, Waccamaw Killifish, and Fundulus sp. “Lake Phelps” Killifish are known to inhabit only freshwater environments.

Fundulus rathbuni
Speckled Killifish – Fundulus rathbuni
Fundulus waccamensis
Waccamw Killifish – Fundulus waccamensis

The Waccamaw basin is home to two of our three species found in only one river basin – Golden Topminnow and Waccamaw Killifish; the other species, Bluefin Killifish is found only in the Cape Fear basin. The Golden Topminnow is a recent, naturally-occurring migrant from South Carolina; it was unknown to occur in North Carolina until 2007 when it was first discovered in Marlowe Branch in Columbus County. The Bluefin Killifish is our state’s only nonindigenous (non-native or introduced) topminnow. Speckled Killifish is suspected of being introduced in the Catawba basin and questionably Fundulus sp. “Lake Phelps” Killifish or perhaps Banded Killifish has been discovered in Shearon Harris Lake in southern Wake County, Cape Fear basin (Tracy et al. 2020).

The Lined Topminnow is our most widely distributed species being found in 11 basins. The Cape Fear basin contains the most species, seven; whereas the Catawba and Lumber basins each have only one species.

Two species were described for the first time from North Carolina. Waccamaw Killifish described in 1946 from Lake Waccamaw in Columbus County (Hubbs and Raney 1946) and Speckled Killifish described in 1889 from several localities in the Haw River watershed in Guilford County (Jordan 1889).

Table 2. Physiographic regions and habitats in which to find North Carolina’s Killifish. Adapted from Hardy (1980), Lee (1980), Shute et al. 1983, Rohde (2009), and Kells and Carpenter (2011).
SpeciesPhysiographic RegionHabitats
Golden Topminnow Southeastern Coastal Plain Open, sunlit, quiet, slow, shallow, warm, heavily vegetated waters of marshes, swamps, lake shores, sloughs, drainage ditches, borrow pits, and creek waters; also occurring in slightly to moderately saline waters
Marsh KillifishEastern Coastal PlainFreshwater rivers and streams and brackish water tidal streams, coastal bays, marshes, channels, and over seagrass flats
Banded KillifishPrimarily northeastern Coastal PlainCalm, slow, and clear water of rivers and creeks, but also occurring from, small inland streams to wide tidal rivers with low salinity, usually over a bottom of open sand
Mummichog Eastern Coastal PlainTidal marshes, creeks, and ditches over mud flats and in or near vegetation, but also often occurring in fresh water
Lined TopminnowSand Hills, Coastal PlainFreshwater, soft-water, dystrophic, acidic, clear or tannin-stained quiet portions of streams, sloughs, drainage ditches, borrow pits, and ponds, especially near submerged or emergent vegetation
Spotfin Killifish Southeastern Coastal PlainEstuarine, typically in intertidal salt marshes
Striped KillifishEastern Coastal PlainPreferring high salinities in inlets, bays, estuaries, marshes, and also along beaches
Speckled KillifishCentral PiedmontFreshwater, common in pools and runs of streams, usually over mud or sand bottoms
Waccamaw KillifishCoastal Plain – Lake WaccamawFreshwater, occurring in large schools in shallow water along the sandy to muddy shoreline, often associated with submerged or emergent vegetation
Fundulus sp. “Lake Phelps” KillifishCoastal Plain – Lake PhelpsFreshwater, occurring in large schools in shallow water along the sandy to muddy shoreline, often associated with submerged or emergent vegetation
Bluefin KillifishWilmington, New Hanover CountyFreshwater, only occurring in the lake and outfall
Rainwater KillifishEastern Coastal PlainSaltwater environments, but also occurring in some freshwater habitats; usually associated with dense vegetation

Because of their limited distributions and anthropogenic impacts upon their habitats, three species are listed as imperiled – Fundulus sp. “Lake Phelps” Killifish, which is Significantly Rare; Waccamaw Killifish which is Special Concern; and Bluefin Killifish which is Special Concern (Krabbenhoft et al. 2009; NCAC 2017; NCNHP 2018; NCWRC 2017).

Lucania goodei
Bluefin Killifish – Lucania goodei

Their identification is relatively straight-forward. Key characteristics for their proper identification include the positioning of the dorsal fin relative to the snout and caudal fin, origin of the dorsal fin relative to the origin of the anal fin; color patterns; number of dorsal fin rays; number of gill rakers, and lateral scale count (please refer to the Identification Key to the Species of Topminnows (Family Fundulidae) in North Carolina). However, several species can co-occur within the same habitats at the same time, rendering field identifications a challenge.

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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