Green Sunfish
Lepomis cyanellus
Description: The Green sunfish (Lepomis cyanellus) has a body that is short and stout, with a length rarely exceeding six inches.1 The head is normally olive in color, with the cheeks randomly spotted and streaked with bluish green. Color of the back is blackish-green to olive- or tannish-green. The sides are greenish with seven to twelve indistinct dark, vertical bars.2 The fins have a yellowish white border and a dark spot is displayed on the second dorsal (top) and anal (bottom) fins. The fin borders of males intensifies during breeding.
Habitat: The Green sunfish is highly adaptable, but
tends to become most abundant in rocky situations, of either lakes
or streams, where other sunfish are absent or uncommon.1 Although
primarily a warm-water fish, Green sunfish will occur, in small
numbers, in marginal trout waters above 2,200 meters (7,200 feet)
elevation.
Total Range: The Green sunfish is native to North America
east of the Continental Divide and west of the Appalachian Mountains,
from the Great Lakes region south to the gulf coastal states and
into northeastern New Mexico.2 This fish has been introduced
into many western states including Arizona, where it now occurs
statewide.
Reproduction: Spawning begins in the spring and continues until late summer in water temperatures between 15-30oC (59-86_F). The eggs are laid in nests scooped out of gravel or sandy silt by the male in shallow water.2 Males often nest close to one another (12-20 inches apart), resulting in an almost constant defensive display of fighting between the males of adjacent territories.1
Diet: Green sunfish feed primarily on aquatic and terrestrial insects, but will also eat crayfish and small fish.2
Threat to Native Species and/or Environments: Green sunfish are remarkably tolerant of crowding among themselves. Under such conditions they often stunt (remain small in size), creating management problems in small lakes.1 Large populations apparently compete with the young of other fishes for food, or prey directly upon them, thus causing negative impacts to both game fish and native species.
Green sunfish in Pima County: Green sunfish can be found in Arivaca Lake and along the perennial reaches of Sabino Canyon Creek. It may also occur in urban lakes within and around the City of Tucson as well as various stock ponds. Efforts have begun to eliminate this species from Sabino Canyon to protect populations of the federally "endangered" Gila topminnow.
References
1 Minckley, W. L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix. Pp. 229-231
2 New Mexico Department of Game and Fish et al. 1998. BISON-M: New Mexico Species List/Species
Accounts. http://www.fw.vt.edu/fishex/states/nm.htm