Article text: Wikipedia contributors, Rio Grande darter (source revision). Licensed under CC BY-SA 4.0. Retrieved 2026-10-11.
Rio Grande Darter
Etheostoma grahami
Percidae · freshwater water fish
2 minute read · Species guide

About Rio Grande Darter
The Rio Grande darter (Etheostoma grahami) is a small species of ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae which includes the perches, ruffs and pike-perches. It is endemic to the lower Rio Grande drainage of the United States and Mexico. It inhabits riffles over substrates of gravel or rubble. This species can reach a length of 6 cm (2.4 in), though most only reach about 3 cm (1.2 in). The Rio Grande darter was first formally described as Oligocephalus grahami in 1859 by the French zoologist Charles Frédéric Girard (1822–1895) with the type locality given as the Devils River in Texas. The specific name honors the American soldier and topographer James Duncan Graham (1795–1865), who led the expedition on which the type was collected by John H. Clark.
Diet and feeding
The FishTraits compilation records these diet categories for this species: invertebrates or larval fish. These are broad categories, not a claim that every individual consumes every example in a category.
Reported feeding positions include bottom feeding and surface or water-column feeding. The compilation combines published observations; diets can vary with age, locality, and available food.
Habitat preferences
Reported habitat associations include medium to large rivers, streams and small rivers, creeks, springs or subterranean waters.
The source records associations with clay or silt, sand, gravel, vegetation. An association indicates reported use, rather than an exclusive requirement.
Reproduction and parental care
The compilation reports a representative maturity age of 1 years. Its maturity field summarizes mean, median, or modal estimates, usually for females; male estimates can be used when female data are unavailable. It is not a fixed age at which every fish first breeds.
Batch or serial spawning has been reported somewhere in the species’ range. This does not establish the same spawning pattern for every population.
Recorded spawning months are Jan, Feb, Mar, Apr, May, Jun for the source’s reporting region (MEX). This is a regional calendar, not a range-wide schedule.
The reproductive-guild classification includes spawning on open substrates without guarding the brood.
Size and recorded longevity
FishTraits reports a maximum total length of 4.4 centimetres. Some entries use an estimated asymptotic length; this value should not be treated as a certified record catch.
Recorded longevity in the compilation is 2 years. Wild observations were preferred, but captive records were accepted where wild records were unavailable, and unspecified records were assumed wild. The value is not a guaranteed wild lifespan or an aquarium life expectancy.
Range
Where it lives
Share of records by state
Habitat
Water and movement
- Water
- WoRMS records this species in fresh water.
- Migration
- Undetermined
Classification
Taxonomy
- Kingdom
- Animalia
- Phylum
- Chordata
- Superclass
- Actinopterygii
- Class
- Teleostei
- Order
- Perciformes
- Family
- Percidae
- Genus
- Etheostoma
- Species
- Etheostoma grahami
- ITIS TSN
- 168397
- WoRMS AphiaID
- 1419863
- GBIF key
- 2382296
Common questions about Rio Grande Darter
What is the scientific name of Rio Grande Darter?
Does Rio Grande Darter live in fresh water or salt water?
Where has Rio Grande Darter been recorded in the United States?
Closest relatives
Other Etheostoma species
Same family