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Tessellated Darter

Tessellated darter

NH Conservation Status: Not listed


State Rank: Secure


Scientific Name: Etheostoma olmstedi


Distribution: The overall range of the tessellated darter is from the St. Lawrence drainage in southern Quebec, the southern tributaries of Lake Ontario, the Connecticut River and coastal streams from Massachusetts to the Altamaha River in Georgia. Tessellated darters are common in the upper Connecticut River watershed. They are relatively rare in the tributaries of the Merrimack River and absent from the Androscoggin, Saco, and coastal drainages.

Description: The tessellated darter can be recognized by dark spots resembling a “W” or an “M” on an elongate, cylinder-shaped body. On its light brown body, two dark streaks extend from the eye; one to the nose and one to the corner of the mouth. The tessellated darter may be distinguished from the swamp darter by its straight lateral line and a distinct groove separating the upper lip from the snout. Growth rarely exceeds two or three inches in length.


Tesselated darter

Its size alone distinguishes this tessellated darter from its smaller cousin, the swamp darter. Another distinguishing characteristic is the groove just above the upper lip, which is lacking in the short, smooth snout of the swamp darter.

Species commonly confused with: Swamp darter


Habitat: The tessellated darter occurs in both flowing and standing waters but it shows a preference for quieter areas and, except during the breeding season, for sand or mud bottoms.


Life History: Male tessellated darters assume a dark, almost black color during their spring breeding. Depending on the local temperature regime, spawning takes place in the spring when the male chooses a location and guards it throughout the hatching of the eggs. Primary food sources include benthic invertebrates, primarily midge larvae, but other organisms, such as amphipods and copepods, are taken in smaller amounts.


Origin: Native


Conservation/Management: Tesselated darters are an important host species for the Federally Endangered dwarf wedge mussel. Mussel larvae, called glochidia, can only be distributed by attaching to the gills of a host fish species. Maintaining healthy populations of tessellated darters is a critical component of efforts to protect and restore dwarf wedge mussel populations in the Connecticut River watershed.




  • Continue to collect baseline data on the distribution and status of tessellated darters and other freshwater fish species throughout New Hampshire.


Distribution Map: (under construction)