Barred Livebearer, Poeciliopsis turrubarensis
Barred Livebearer, Poeciliopsis turrubarensis. Fish caught from a freshwater stream in Puerto Chomes, Costa Rica, March 2021. Length: 8.0 cm (3.2 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
The Barred Livebearer, Poeciliopsis turrubarensis, is a member of the Livebearer or Poeciliidae Family, that is also known as the Turraba Toothcarp and in Mexico as guatopote del Pacifico. There are twenty-four species in the genus Poeciliopsis, of which nineteen are found in Mexican freshwater systems that feed into the Atlantic and/or the Pacific Oceans.
The Barred Livebearer has an elongated body that has a depth that is 25% to 31% of standard length. They are olive dorsally transitioning to gray ventrally with 6 to 10 well defined dark bars on the flanks on the front three-fourths of the body. They have a dark line along the midline of the flank that runs from the anal fin to the caudal fin. Their fins are dusky. The males have yellow belly. Their head is small and rounded with an upper straight profile, a small mouth that has a series of large outer teeth and low-set large eyes. Their anal fin is rounded with 2 spines and 6 to 8 rounded rays (with males having larger fins than females); their caudal peduncle is thick and their caudal fin is rounded; their dorsal fin has 1 spine and 7 rays that originates over the last rays of the anal fin; their pectoral fins are midsized and reach the middle of the pelvic fins; and, their pelvic fins and 7 or 8 rays. The males have a tube on their left side formed by folded anal fin rays that function as a sex organ. They have 15 to 22 gill rakers. They are covered with smooth scales. They have a prominent lateral line.
The Barred Livebearer is a benthopelagic non-migratory species that are found in both coastal brackish and freshwater habitats in lagoons, estuaries and steams over sandy and mud substrate at elevations up to 120 m (400 feet) at depths up to 5 m (17 feet) in water temperatures between 23°C (74°F) and 28°C (82°F). They are commonly found at river mouths and are known to associate with the Pacific Four-eyed Fish, Anableps dowei. They can also survive in brackish and sea waters with elevated salinities. They are sexually dimorphic with females having a maximum length of 9.0 cm (3.5 inches) and males 4.0 cm (1.6 inches). Reproduction is viviparous and involves internal fertilization with gestation periods of 4 weeks. Each female can produce broods of 10 to 50 live young. They are primarily herbivores that feed on algae, diatoms, detritus and ooze. In turn they are preyed upon by various pelagic and surface predatory fish as well as numerous seabirds, including herons. The Barred Livebearer is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Barred Livebearer is found in Mexico’s freshwater drainage systems of the Pacific Slope from Jalisco south to Guatemala.
The Barred Livebearer is easily confused with the Blackstripe Livebearer, Poeciliopsis prolifica (no bars on the sides), the Lowland Livebearer, Poeciliopsis latidens (seven to twelve short bars on the sides), and the San Jerónimo Livebearer, Poeciliopsis fasciata (three to five bars on the sides).
From a conservation perspective the Barred Livebearer in currently considered to be of Least Concern, with stable, widely distributed populations. They are small in stature and of limited interest to most. Their long-term viability is threatened by human development that changes their native habitats.