Rainbow Darter
(Etheostoma caeruleum)
Taxonomy
Kingdom Animalia Phylum Chordata Class Actinopterygii Order Perciformes Family Percidae Genus Etheostoma Subgenus Oligocephalus Species caeruleum |
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Video: E. caeruleum males and females in an aquarium with example of male displays
Identifying Characteristics
As their name suggests, the rainbow darter is one of the most colorful fish in the Boneyard Creek. This species exhibits sexual dimorphism, with males exhibiting bright nuptial coloration during the breeding season (in the spring, usually late February through May), whereas females remain a drab, cryptic brown color year round. Both sexes are deep bodied with the deepest part occurring under the center of the first dorsal fin.
There are 8-13 vertical, dark lateral bars present on the side of the fish:
- In breeding males, the bars are blue with red in between.
- In females and in non-breeding males, the bars are dark brown with lighter tan coloration in between.
The dorsal, anal, and caudal fins are red with faint blue edges in breeding males and there is sometimes faint fin coloration present in females. Female and non-breeding males may have a teardrop marking present under the eye. In addition, there are 6 - 10 dorsal saddles along the back of the fish, and 3 of the saddles are very dark and prominent . Other characteristics of this species include an unscaled breast and cheek and 13 pectoral rays.
The average size of these fishes is 5-7 cm and their lifespan is known to be around 2 - 4 years.
Habitat
Rainbow darters can be found in gravel and rubble riffles in fast flowing creeks and small to medium rivers.
Rainbow darters can be found in gravel and rubble riffles in fast flowing creeks and small to medium rivers.
Life History
Breeding occurs when water temperature is 17-18 C in the spring. This varies by location but is usually around April-May. Males defend their territory in shallow riffles. The blue coloration in males becomes more intense. A female lays 3-7 eggs for each spawning act. The eggs are fertilized and fall in the gravel with no parental care. This may be repeated many times over several days during the breeding season. A female can lay 800-1000 eggs each season. The eggs hatch in 10 to 11.5 days.
Geographic Range
Rainbow darters have a wide range throughout the eastern United States that includes the Great Lakes and Mississippi River basins
from western New York and southern Ontario to Minnesota, and south to Arkansas
and northern Alabama. Isolated populations also occur along Mississippi River.
Diet
Rainbow darters will eat copepods, small snails and crayfish, minnow and lamprey eggs, watermites, waterfleas, and larvae of midge, mayfly, stonefly, and caddisfly. Darters are predated by large freshwater fish especially stonecats, burbot, and smallmouth bass.
Rainbow darters will eat copepods, small snails and crayfish, minnow and lamprey eggs, watermites, waterfleas, and larvae of midge, mayfly, stonefly, and caddisfly. Darters are predated by large freshwater fish especially stonecats, burbot, and smallmouth bass.
Conservation Status
No special status, however the Rainbow Darter is commonly a biological indicator of water quality because it is not tolerant of most water pollutants. Most likely scarce in Boneyard creek due to poor water quality. One male rainbow darter was caught via seine in Fall 2014 by the UIUC Icthyology class.
Similar species:
Orangethroat Darter, E. spectabile - lack red on anal fin, 11-12 pectoral rays, dorsal saddles evenly colored
Redband Darter, E. luteovinctum - lack red on anal fin, partly scaled cheek
Mud Darter, E. asprigene - lack red on anal fin, scales on cheek
Gulf Darter, E. swaini - scales on cheek
Orangethroat Darter, E. spectabile - lack red on anal fin, 11-12 pectoral rays, dorsal saddles evenly colored
Redband Darter, E. luteovinctum - lack red on anal fin, partly scaled cheek
Mud Darter, E. asprigene - lack red on anal fin, scales on cheek
Gulf Darter, E. swaini - scales on cheek
Sources:
http://www.michigan.gov/dnr/0,4570,7-153-10370_12145_12203-58742--,00.html
http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=809
http://animaldiversity.ummz.umich.edu/accounts/Etheostoma_caeruleum/
http://www.dnr.state.oh.us/Home/species_a_to_z/SpeciesGuideIndex/rainbowdarter/tabid/6732/Default.aspx
http://hatch.cehd.umn.edu/research/fish/fishes/rainbow_darter.html
http://www.inhs.illinois.edu/cbd/ilspecies/fishmaps/et_caerule.gif
http://sitemaker.umich.edu/mi.lakes.statustrends/percidae__perch__darters__etc._
http://www.michigan.gov/dnr/0,4570,7-153-10370_12145_12203-58742--,00.html
http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=809
http://animaldiversity.ummz.umich.edu/accounts/Etheostoma_caeruleum/
http://www.dnr.state.oh.us/Home/species_a_to_z/SpeciesGuideIndex/rainbowdarter/tabid/6732/Default.aspx
http://hatch.cehd.umn.edu/research/fish/fishes/rainbow_darter.html
http://www.inhs.illinois.edu/cbd/ilspecies/fishmaps/et_caerule.gif
http://sitemaker.umich.edu/mi.lakes.statustrends/percidae__perch__darters__etc._