The Jack Dempsey (''Rocio octofasciata'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of cichlid fish that is native to freshwater habitats from southern Mexico to Honduras, but also introduced elsewhere. Its common name refers to its aggressive nature and strong facial features, likened to that of the famous 1920s boxer

Jack Dempsey William Harrison "Jack" Dempsey (June 24, 1895 – May 31, 1983), nicknamed Kid Blackie and The Manassa Mauler, was an American professional boxer who competed from 1914 to 1927, and reigned as the world heavyweight champion from 1919 to 1926 ...

.Jack Dempsey Cichlid
Animal-World.com

Distribution

The fish is native to freshwater habitats from southern Mexico to Honduras, where it is found in slow-moving waters, such as swampy areas with warm, murky water, weedy, mud- and sand-bottomed canals, drainage ditches, and rivers. It is also established as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

in Australia, the United States and

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

(presumably as an aquarium escapee) These are locally known as the Mexican Blue Frontosa.

Ecology

The Jack Dempsey natively lives in a

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

climate and prefers water with a pH of 6-7, a water hardness of 9–20 dGH, and a temperature range of . Males can reach up to 10in length. It is carnivorous, eating worms,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s and other fish.

Reproduction

Jack Dempseys lay their eggs on a flat hard surface within their territory, such as rocks, logs, or the glass bottom of an aquarium. Like most cichlids, they show substantial

parental care Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal ki ...

: both parents help incubate the eggs and guard the fry when they hatch. Jack Dempseys are known to be attentive parents, pre-chewing food to feed to their offspring. However, it is not uncommon for them to eat their fry when the breeding pair are overly disturbed or something in their environment is wrong.

Morphology

The coloration changes as the fish matures from a light gray or tan with faint turquoise flecks to a dark purple-gray with very bright, iridescent blue, green, and gold flecks. Their colors change under stress. The dorsal and anal fins of mature males have long, pointed tips. Females lack these exaggerated tips. During breeding both genders considerably darken in color, appearing almost black with little to no metallic coloration. Different variations of color are also available on the aquarium market. Color variants include Gold, Electric Blue, and pink (a fish that displays both gold & blue traits)

In the aquarium

The fish is a popular aquarium fish, due to its striking appearance and personable mannerisms. It, like most cichlids, is considered "aggressive", but can get along in a well-populated tank, tending to be more territorial if kept with only a few other fish, therefore allowed to easily establish and defend a "territory" in the tank. Jack Dempsey cichlids can often appear shy, hiding away in cave work. It is recommended that the Jack Dempsey cichlid is provided with plenty of places to hide. They will often claim a cave first and be very aggressive to other tank mates that swim near its home. There is also a blue variant of this fish which commonly known as the blue Jack Dempsey or electric blue Jack Dempsey. This is natural genetic mutation. The blue counterpart is less aggressive, smaller in size and more delicate.

References