Jack Dempsey Fish - not an Easy Fish to Keep
The Jack Dempsey (Cichlasoma octofasciatum) is a cichlid fish
named for the 1920's boxer Jack Dempsey. The name alludes to its
aggressive nature. 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. While it is a popular aquarium fish, due to its
behavior it is not easy to keep.
Jack Dempsey Color Variations
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. The dorsal and
anal fins of mature males have long, pointed tips. Females lack
these exaggerated tips.
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 escape). The Jack Dempsey natively lives in a tropical
climate and prefers water with a 7.0 - 8.0 pH, a water hardness
of 9 - 20 dGH, and a temperature range of 72 - 86 °F (22 - 30
°C). It can reach up to 25 cm (10 in) in length. It is
carnivorous, eating worms, crustaceans, insects and other fish.
Picture Jack Dempsey
Jack Dempsey Breeding
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.
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.