Red Shiner, Cyprinella lutrensis
The Red Shiner, Cyprinella lutrensis, whose common Spanish name is carpita roja, is a species in the Carps and Minnows or Cyprinidae Family, known collectively as carpas and carpitas in Mexico. Globally, there are 32 species in the genus Cyprinella, of which eight are widespread throughout Mexico’s freshwater systems.
The Red Shiners have deep, wide, and laterally compressed bodies that are deepest anterior of the dorsal fin origin. They are olive green dorsally transitioning to silvery on their sides and to white ventrally. When breeding, males have iridescent pink-purple-blue sides, a red crown, and red tips on all their fins except for the dorsal fin. Their head is sharp and compressed with small eyes and a terminal to slightly subterminal mouth. Males have a sharply pointed snout that overhangs their mouth. Their anal fin has 8 to 10 rays; their caudal peduncle is wide; their caudal fin is concave; their dorsal fin has 8 rays; and their pelvic fins have 8 rays.
The Red Shiners are a non-migrant mid-water schooling freshwater species found in a wide variety of aquatic habitats, including backwaters, creek mouths, streams containing sand and silt, riffles, and pools. They are small fish that reach a maximum length of 9.0 cm (3.5 inches) with females being larger than males. They are tolerant of high turbidity, siltation, and temperatures up to 35oC (96oF). They feed on terrestrial and aquatic insects and algae. Spawning occurs in tranquil waters with males selecting the location and protecting it. Females are known to produce sounds to attract males. Reproduction is seasonal and occurs via broadcasting into crevices; sticky eggs attach themselves to rocks and vegetation. Each female can release up to 16 batches of eggs per day with 10 to 70 eggs per batch and about 6,000 eggs released annually. They have a lifespan of up to three years.
The Red Shiners are fairly widespread and are found in all freshwater systems of northern mainland Mexico.
The Red Shiner can be easily confused with the Blacktail Shiner, Cyprinella venusta (narrower body; distinct caudal spot), the Plateau Shiner, Cyprinella lepida (breeding male with green back, yellow-purple sides, gold-orange head, and yellow-orange fins), and the Proserpine Shiner, Cyprinella proserpina (black stripe on sides; black stripe on chin and throat).
The Red Shiners are often used as bait fish and are also a component of the aquarium trade. From a conservation perspective, they are considered of Least Concern. They are highly invasive and widespread with populations in excess of 1 million. They have widely spread due to human intervention via aquarium releases, bait bucket releases, introduction as forage fish, and farm escapes. They are known to devastate local populations via consumption of food sources, consumption of eggs and larvae of native fish, hybridization with Blacktail and Blue Shiners, and introduction of tapeworms. Efforts to eradicate this species from several bodies of water have proven very difficult.
Red Shiner, Cyprinella lutrensis, Breeding Male. Fish caught from Sand Creek, Montezuma, Illinois, August 2014. Length: 9.0 cm (3.5 inches). Catch, photo, and identification courtesy of Josh Leisen (lifelistfishing.com), Gaylord, MI.