The Jack Dempsey (Archocentrus octofasciatus (Regan, 1903), formerly Nandopsis octofasciatum and Cichlasoma octofasciatum) is a cichlid fish that is widely distributed across North and Central America (from Mexico south to Honduras). Its common name refers to its aggressive nature, likened to that of the famous 1920s boxer Jack Dempsey.
The fish is native to Yucatan and Central America, 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 in Australia, the USA and Thailand (presumably as an aquarium escapee).
The Jack Dempsey natively lives in a tropical climate and prefers water with a pH of 7-8, a water hardness of 920 dGH, and a temperature range of 2230 ?C. It can reach up to 25 cm in length. It is carnivorous, eating worms, crustaceans, insects and other fish. It can eat platies when it is three inches long.
Jack Dempseys lay their eggs on the substrate (the bottom of the aquarium or pool). Like most cichlids, they show substantial parental care: 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. A lot of times however they will eat their fry when the breeding pair are overly disturbed or something in their environment is wrong.
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.
Like most cichlids it is territorial, especially against its own kind and similar species. The fish was once very popular due to its striking appearance and personable mannerisms. It is a popular aquarium fish.
In 1997 the San Francisco Chronicle reported that a man had died when he put a Jack Dempsey into his mouth as a joke: the fish presumably erected its fin spines to avoid being swallowed, a characteristic cichlid anti-predator response, and became wedged in the man's throat.
In a second season episode of Homicide: Life on the Street, a Jack Dempsey is recovered at the scene of a murder, and is taken home by an unsuspecting Detective John Munch, who intends to give it to his tropical fish-collecting girlfriend as a present. As a surprise, he places the fish in her aquarium, where it proceeds to devour $4,000 worth of her fish before being removed. Munch later refers to the fish as an "assassin" who "uses piranhas as toothpicks."
More than 225 species, with estimates of 300 species, of cichlids are found throughout South America. An estimated 75% of these inhabit the mighty Amazon River Basin. Cichlids are also found in Central America, where they are well-known for their pugnacious behavior and their stunning colors. Most of these cichlid are large, thus requiring large tanks. These fish inhabit most types of water ways throughout Central America including lakes, streams, rivers, even underground water sources.
Their colorful appearance, the many different species available, their behavior and their breeding are just some of the reasons the Cichlids are one of the most popular aquarium fish.
Due to their aggressive behavior, the tank for cichlids should be as large as possible, with its length being more critical than its height; meaning the longer the better.
In the Cichlid tank there must be places of refuge. These can be rock caves, large pieces of driftwood or even inverted flowerpots. Most large species of Cichlids will dig up the substrate material, and occasionally will remove plants from the substrate. The Angelfish, Discus and the dwarf species Apistogramma all prefer a densely planted tank.
The water temperature should be in the range of 24-28 degrees celsius, slightly higher for the Discus. The diet should consist of live and frozen food of all kinds as well a large flake staple food. Large specimens can be feed Earthworms, garden Crickets and kitchen leftovers.