What do they look like?

Lepomis cyanellus, like the other members of the Centrarchidae family, is brightly colored. In comparison to the other members it has a wider body (more cigar shaped) and a much larger mouth. They do not grow large enough to be considered desirable “pan-fish,” because their average length is only 12.7 to 15.24 centimeters. This is sometimes due to overpopulation, which can stunt growth. Lepomis cyanellus is blue-green in color with scattered dots of black and a white to yellow belly. They have a dark spot on the soft spinous portion of the dorsal fin, and sometimes a spot on the posterior portion of their anal fin. Females have dusky colored bars on the dorsolateral portion of their body. Immature individuals lack striking color patterns, and instead are plain gray without bands. Breeding males normally have an orange tint to the anal, caudal, pelvic, and posterior dorsal fins and vivid black, orange, and white color on their anal fin. Lepomis cyanellus has palatine teeth and 28 to 29 vertebrae. Entier and Starnes (2001) state that L. cyanellus typically has “anal fin soft rays 9 to 10 (8 to 11). Pectoral fin rays 13 to 15. Gill rakers 11 to 14.”

Where in the world do they live?

Lepomis cyanellus occurs in central North America, from the plains east of the Rocky Mountain range and west of the Appalachian mountain range, including northeastern Mexico and southeastern Canada. L. cyanellus have been introduced and established in a majority of the continental United States, with the exception of Florida and a few northeastern states. Lepomis cyanellus has been introduced to Africa, South America, Asia, and Europe as an exotic species.

What kind of habitat do they need?

Lepomis cyanellus is a species with a wide tolerance to many different aquatic conditions, one reason why they have been successfully introduced elsewhere. They prefer smaller, sluggish streams and ponds, but can also inhabit lakes with weedy shorelines and slow rivers. They tolerate both turbid and clear water.

How do they grow?

Lepomis cyanellus embryos normally hatch in 2 days. Males guard them for another 5 to 7 days, until the young are able to swim to the top to feed.

How do they reproduce?

Lepomis cyanellus males normally build nests in sunny areas with a gravel substrate and preferably with cover, like rocks, logs, or clumps of grass. They construct depressions by forceful movement of their caudal fins in shallow water (4 to 355 cm deep). The nests are constructed in both colonies and singularly. The nests are aggressively defended by males. Spawning normally occurs 1 to 2 days after nest construction, when a male leads a female to his nest with the production of sounds. They then swim in circles above the nest before they actually spawn. Males can spawn with several females simultaneously.

Spawning occurs in Lepomis cyanellus when the water rises above 21 degrees Celsius (70 degrees Fahrenheit). It is thought that L. cyanellus may produce the same number of eggs as Lepomis macrochirus, which is roughly 50,000. It takes normally 1 to 2 days for the eggs to hatch and another 5 to 7 days of protection from the male until they become independent (Parr, 2002).

Lepomis cyanellus males are caretakers of the young. Males start by fanning the eggs to promote oxygenation. They defend nests from predators before and after hatching.

How long do they live?

Lepomis cyanellus typically live between 4 and 6 years in the wild.

How do they behave?

Lepomis cyanellus is an aggressive species that outcompetes native species where they have been introduced. They are mainly solitary, but occur in loose aggregations, especially in breeding seasons. They are active during the day.

How do they communicate with each other?

Because L. cyanellus males lack dusky bars, it could be suggested that the bright and bold colors are means to attract females through visual cues. Males also produce sounds during mating.

What do they eat?

Green sunfish are dietary generalists. Green sunfish larvae consume various types of zooplankton and, as they grow, they expand their diets to include insect larvae and small snails. As juveniles and adults their diets expand to add small crayfish, fish eggs, insects, and small fish. It should be noted that, as competition decreases, their average prey size increases.

What eats them and how do they avoid being eaten?

Green sunfish, like other members of the family Centrarchidae, have young with a less colorful appearance; they are camouflaged to blend in with vegetation (Entier and Starnes, 2001). Their most common aquatic predators are largemouth bass (Micropterus salmoides) ; channel catfish (Ictalurus punctatus) ; flathead catfish (Pylodictis olivaris); and bullhead catfish (Ameiurus) (Paulson and Hatch, 2004; Chizinski and Pope, 2003).

What roles do they have in the ecosystem?

Lepomis cyanellus is both a predator and prey, therefore it is a means of transferring energy through the food chain. Since it is such an aggressive species it commonly out competes native fish and affects populations of other aquatic organisms such as crayfish and freshwater mussels.

Do they cause problems?

Lepomis cyanellus is problematic for fish management because they often outcompete native fish. These fish have become an issue in bass-bluegill poulation management.

How do they interact with us?

Although L. cyanellus is barely suitable as a "pan-fish," they can be exciting to catch. They have a tendency to attack almost any bait and provide a tough fight for anglers, given their size.

Are they endangered?

Lepomis cyanellus is not listed endangered or threatened either nationally or internationally. They are common and abundant throughout their range.

Some more information...

Hybridization, which is reproduction between two different species, is very common in L. cyanellus. Hybrids tend to be mostly males and grow faster than either of the parent species. Bluegill (Lepomis macrochirus) and longear sunfish (Lepomis megalotis) are common species that Lepomis cyanellus crossbreeds with. Lepomis megalotis and L. cyanellus hybrids are commonly known as “hybrid bluegills”. (Entier and Starnes, 2001; www.Kentuckyawake.org)

ETYMOLOGY: “Lepomis” means scaled operculum and “cyanellus” means blue.

Contributors

Emily Clemons, Eastern Kentucky University

Sherry Harrel, Eastern Kentucky University

Contributors

Tanya Dewey, Animal Diversity Web, University of Michigan Museum of Zoology

References

Etnier, D., W. Starnes. 2001. The Fishes of Tennessee. Knoxville: The University of Tennessee Press.

Paulson, N., J. Hatch. 2004. "Minnesota Depatment of Natural Resources' MinnAqua Aquatic Program" (On-line). Accessed October 27, 2005 at https://ekumail.eku.edu/exchweb/bin/redir.asp?URL=http://www.gen.umn.edu/research/fish/fishes/green_sunfish.html%23reproduction.

Chizinski, C., K. Pope. 2003. Importance of food Ration and Water Temperature on Growth of Juvenile Green Sunfish (Lepomis cyanellus). The Texas Journal of Science, 55/3: 263.

HAAG, W., M. WARREN, M. SHILLINGSFORDa. 1998. Host Fishes and Host-attracting Behavior of Lampsilis altilis and Villosa vibex. The American Midland Naturalist, 141/1: 149-157. Accessed October 29, 2005 at http://www.bioone.org.libproxy.eku.edu/bioone/?request=get-abstract&issn=0003-0031&volume=141&issue=01&page=0149.

Hammerson, G. 1993. "Lepomis cyanellus" (On-line). NatureServe Explorer. Accessed October 27, 2005 at https://ekumail.eku.edu/exchweb/bin/redir.asp?URL=http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Lepomis%2520cyanellus.

2003. "AWAKE Plants and Wildlife" (On-line). Accessed October 27, 2005 at http://www.kentuckyawake.org/templates/plantsWildlife/lifehistory.cfm?instanceID=18954.

Page, L., . Burr. 7/2005. "Lepomis cyanellus, Green Sunfish" (On-line). FishBase. Accessed October 27, 2005 at http://fishbase.org/Summary/speciesSummary.php?ID=3371&genusname=Lepomis&speciesname=cyanellus.