The green sunfish (Lepomis cyanellus) is a species of freshwater fish in the sunfish family (family Centrarchidae) of order Perciformes. A panfish popular with anglers, the green sunfish is also kept as an aquarium fish by hobbyists. They are usually caught by accident, while fishing for other game fish. Green sunfish can be caught with live bait such as nightcrawlers, waxworms, and mealworms. Grocery store baits such as pieces of hot dog or corn kernels can even catch fish. Small lures have been known to occasionally catch Green Sunfish.
The green sunfish is said to have polarization sensitive vision not found in humans and other vertebrates mostly which helps in enhancement of visibility of target objects in scattering media, using a method called polarization difference imaging.
Geographic Distribution 
The green sunfish is native to a wide area of North America east of the Rocky Mountains, from the Hudson Bay basin in Canada, to the Gulf Coast in the United States, and northern Mexico. They are specifically indigenous to a number of lakes and rivers such as the Great Lakes and some of the basins of the Mississippi river. Green sunfish have been introduced to many bodies of water all across the United States and therefore are frequently encountered (Page et al. 1991, p. 267). L. cyanellus has been transplanted to many countries in Africa, Asia, and Europe, in some of which it has become established.
The green sunfish is blue-green in color on its back and sides with yellow-flecked bony-ridge scales called ctenoid scales, as well as yellow coloration on the ventral sides. They also have a dark spot located near the back end of the dorsal fin, the bases of the anal fins (Philips et al. 1982, p. 208; Page et al. 1991, p. 267) and on the ear plate ("Green Sunfish"). It has a relatively big mouth and long snout that extends to beneath the middle of the eye (Philips et al. 1982, p. 208; Page et al. 1991, p. 267). Its pectoral fins are short with rounded edges containing 13-14 pectoral fin rays (Page et al. 1991, p. 267), a dorsal fin with approximately ten dorsal spines ("Green Sunfish: Identification") and a homocercal tail. The typical length ranges from about 3-7 inches and usually weighs less than a pound ("Green Sunfish"). The green sunfish reaches a maximum recorded length of about 30 cm (12 in), with a maximum recorded weight of 960 g (2.2 lb). Identification of sunfish species from one another can sometimes be difficult as these species frequently hybridize (Philips et al. 1982, p. 208-209).
The species prefers vegetated areas in sluggish backwaters, lakes, and ponds with gravel, sand, or bedrock bottoms. They also can be found in very muddy waters and are able to tolerate poor water conditions. Green sunfish tend to spend their time hiding around rocks, submerged logs and other objects that provide cover and protection ("Green Sunfish").
Green sunfish begin spawning in the summer with the exact time varying with location and water temperature. When they do spawn, the males create nests in shallow water by clearing depressions in the bottom (Philips et al. 1982, p. 209), often near a type of shelter such as rocks or submerged logs (Paulson 2004). He then defends his nest from other males using visual displays and physical force when necessary (Paulson 2004). On occasion simply constructing a nest is sufficient for the male to attract a mate but when it is not he will court her with grunts and lead her to his nest.
They continue their courtship dance, swimming with each other around the nest until the female descend to deposit her eggs in the nest. The female will lay anywhere from 2,000 to 26,000 eggs and leave them for the male to guard. He keeps watch over them until they hatch in 3 to 5 days, all the while protecting them and fanning them with his fins, keeping them clean and providing them with oxygenated water. When they hatch the fish remain near the nest for a few days, then leave to feed and fend for themselves (Paulson 2004). After the eggs have hatched the male will often seek to attract another female to lay her eggs in his nest ("Green Sunfish: Identification").
Green sunfish tend to nest in areas close to other green sunfish as well as other species of sunfish. Due to the close proximity of multiple nests a green sunfish female may deposit some of her eggs into the nest of a male of a different species. This in turn leads to the next generation containing some amount of hybrids (Paulson 2004). These green sunfish hybrids will often look like a combination of its parents, often making it difficult to distinguish one species from another (Philips et al. 1982, p. 209).
The generic name Lepomis derives from the Greek λεπίς (scale) and πώμα (cover, plug, operculum). The specific epithet, cyanellus, derives from the Greek κυανός (blue).
- FishBase: Lepomis cyanellus
- ITIS: Lepomis cyanellus
- Ellis, Jack (1993). The Sunfishes-A Fly Fishing Journey of Discovery. Bennington, VT: Abenaki Publishers, Inc. ISBN 0-936644-17-6.
- Rice, F. Philip (1964). America's Favorite Fishing-A Complete Guide to Angling for Panfish. New York: Harper Row.
- Rice, F. Philip (1984). Panfishing. New York: Stackpole Books. ISBN 0-943822-25-4.
- Malo, John (1981). Fly-Fishing for Panfish. Minneapolis, Minnesota: Dillon Press Inc. ISBN 0-87518-208-9.
- Axelrod, Herbert R. et al. (2007) Dr. Axelrod's Atlas of freshwater aquarium fishes T.F.H. Publications, Neptune City, New Jersey, ISBN 978-0-7938-0616-4
- Philips, Gary, Schmid, W., Underhill, J. (1982) "Fishes of the Minnesota Region". University of Minnesota Press, Minneapolis, Minnesota, ISBN 0-8166-0979-9
- Page, Lawrence, Burr, B. (1991) "A Field Guide to Freshwater Fishes". Houghton Mifflin Company, Boston, New York, ISBN 0-395-91091-9
- "Green Sunfish." Ohio Department of Natural Resources - Camping, Boating, Fishing, Hunting, Biking, Hiking in Ohio. Web. 26 Apr. 2011. <http://www.dnr.state.oh.us/Home/species_a_to_z/SpeciesGuideIndex/greensunfish/tabid/6655/Default.aspx>.
- "Sunfish Biology and Identification: Minnesota DNR." Minnesota Department of Natural Resources: Minnesota DNR. Web. 26 Apr. 2011. <http://www.dnr.state.mn.us/fish/sunfish/biology.html>.
- "Green Sunfish: Identifying Characteristics." Wyoming Game and Fish - Home - 1. Web. 26 Apr. 2011. <http://gf.state.wy.us/fishexam/species/frmGreenSunfish.aspx>.
- Paulson, Nicole, and Jay T. Hatch. "Fishes of Minnesota-Green Sunfish." Green Sunfish. Minnesota Department of Natural Resources' MinnAqua Aquatic Program, 25 Aug. 2004. Web. 30 Apr. 2011. <http://hatch.cehd.umn.edu/research/fish/fishes/green_sunfish.html>.
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