Convict Cichlid, Amatitlania nigrofasciata
Convict Cichlid, Amatitlania nigrofasciata, Female. Fish caught from a fresh water canal, Tampa, Florida, November 2020. Length: 6.5 cm (2.6 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.
Convict Cichlid, Amatitlania nigrofasciata, Male. Fish caught from a fresh water canal, Santa Clarita, California, December 2019. Length: 7.5 cm (3.0 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.
The Convict Cichlid, Amatitlania nigrofasciata, is a member of the Cichlid and Tilapia or Cichlidae Family, that is also known as the Zebra Cichlid and in Mexico as mojarra congo. Globally, there are nine species in the genus Amatitlania, of which one, this species, is found in the freshwater systems of Mexico. Its common name stems from its resemblance to the black striped uniforms of British convicts.
The Convict Cichlid has a “bluegill-like” oval profile with a significant variation in color amongst individuals but they generally have a blue-gray body and a dark blotch on the gill cover. They have 8 or 9 black vertical bars on their side. They are sexually dimorphic with males being larger than females with more pointed fins and darker in color. Mature males also have a humped forehead. The juveniles are a uniform blue-gray color. Their anal fins are long with pointed tips with 8 to 10 spines and 6 or 7 rays; their dorsal fin is long with a pointed tip with 17 to 19 spines and 7 to 9 rays; and the pectoral fins are long extending past the anal fin origin. The fins in the males are longer than those in the female. The lower jaw extends beyond the upper jaw.
The Convict Cichlid is a freshwater fish that is non-migratory and found in slow moving waters that lakes and streams within rocky structure, sunken branches and rock with temperatures between 26oC (79oF) to 29oC (84oF) at elevations up to 1,500 m (4,920 feet). They reach a maximum length of 12 cm (4.7 inches) with males being larger than females. The Convict Cichlid are active diurnally and forage in large schools that consume algae, crustaceans, fish, insects, plants, and worms. The retreat to the cover of caves at night. Breeding occurs in monogamous pairs that spawn in small caves and rock crevices to avoid predation. During breeding season the males become highly aggressive. The females lay from 100 to 150 eggs that attached themselves to flat hard surface within logs and rocks. The eggs will hatch within 3 days and they become free swimming in another three days. The females guard the eggs until they hatch and the both parents will guard the young for four to six weeks with the males being more aggressive towards intruders until they become free swimming. They reach sexual maturity within six months with each female laying eggs only once per year.
The Convict Cichlid native to all countries of Central America but is not native to Mexico. They were introduced to the Balsas River basin in central Mexico in 1987 where it immediately went into conflict with the native Mexican Mojarra, Cichlassoma istlanum. They are currently found in numerous other fresh water systems throughout Mexico.
The Convict Cichlid is very similar to several Black Bases, Sunfishes and Tilapia but differ in that unlike tilapia and most sunfishes, which typically have 3 spines on the anal fin, Convict Cichlids have 7 to 9. The pronounced “hump” found on the head of adult males is not present in Tilapia. They also have a single nostril opening on each side of the head and a broken two-part lateral line not found in Sunfishes and Tilapia.
From a conservation perspective the Convict Cichlid has not been formally evaluated. They are considered to be highly invasive species that compete for food, space and spawning habitat. They are a popular aquarium fish but require waters with elevated temperatures. They are compatible with other fishes of their same size except while breeding when they become extremely aggressive. Almost all aquarium fish are raised in captivity as they are prolific breeders. They have also been utilized as a biological research model of behavior.