Distribution
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.[1] It is also established as an introduced species in Australia, the USA and Thailand (presumably as an aquarium escapee).[3]
Ecology
The Jack Dempsey natively lives in a tropical climate and prefers water with a pH of 7-8, a water hardness of 9–20 dGH, and a temperature range of 22–30 °C (72–86 °F). It can reach up to 25 cm (10 in) in length. It is carnivorous, eating worms, crustaceans, insects and other fish. It can eat platys when it is three inches long. [1
Reproduction
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.
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. The dorsal and anal fins of mature males have long, pointed tips. Females lack these exaggerated tips.
In the aquarium
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 and size it is not easy to keep.
Trivia
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.[4]
http://en.wikipedia.org/wiki/Jack_Dempsey_%28fish%29
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12/01/2008
Jack Dempsey (fish)
Oscar cichlid (fish)
A. ocellatus have been reported to grow to a length of 45 cm (approximately 18 in) and a mass of 1.6 kg (3.5 lb).[1] The wild caught forms of the species are typically darkly coloured with orange ringed-spots or ocelli on the caudal peduncle and on the dorsal fin.[5] It has been suggested that these ocelli function to limit fin-nipping by piranha (Serrasalmus spp.) which co-occur with A. ocellatus in its natural environment.[7] Further studies have suggested the ocelli may also be important for intraspecific communication.[8] The species is also able to rapidly alter its colouration, a trait which facilitates ritualised territorial and combat behaviours amongst conspecifics.[9] Juvenile A. ocellatus have a different colouration to adults and are striped with white and orange wavy bands and have spotted heads.[8]
A. ocellatus is native to Peru, Colombia, Brazil and French Guiana and occurs in the Amazon river basin, along the Amazonas, Içá, Negro, Solimões and Ucayali river systems, and also in the Approuague and Oyapock drainages.[1][2] In its natural environment the species typically occurs in slow moving white-water habitats, and has been observed sheltering under submerged branches.[5] Feral populations also occur in China,[10] northern Australia,[11] and Florida, USA[12] as a by-product of the ornamental fish trade. The species is limited in its distribution by its intolerance of cooler water temperatures, the lower lethal limit for the species is 12.9 °C (55.2 °F).[13]
Although the species is widely regarded as sexually monomorphic,[5] it has also been suggested that males grow more quickly, and in some naturally occurring strains, males are noted to possess dark blotches on the base of the dorsal fin.[8][6] The species reaches sexual maturity at approximately 1 year of age and continues to reproduce for 9-10 years. Frequency and timing of spawning may be related to the occurrence of rain.[14] A. ocellatus are biparental substrate spawners though detailed information regarding their reproduction in the wild are scarce. It has been observed that the closely related Astronotus crassipinnis may, in times of danger, protect its fry in its mouth in a manner reminiscent of mouthbrooding geophagine cichlids. This behaviour, however, has not yet been observed in A. ocellatus.[6] In captivity pairs are known to select and clean generally flattened horizontal or vertical surfaces on which to lay their 1000 to 3000 eggs. Like most cichlids, A. ocellatus practice brood care, although the duration of brood care in the wild remains unknown.[6]
Examination of the stomach contents of A. ocellatus by Winemiller (1990) demonstrated that the natural diet of this fish consists primarily of aquatic and terrestrial insects (which comprise up to 60% of the diet), although small fish, and to a lesser extent crustaceans, are also consumed. Most fish eaten by A. ocellatus in the wild were relatively sedentary catfish, and included Bunocephalus, Rineloricaria and Ochmacanthus species.[7] The species uses a suction mechanism, generated by jaw extension, to capture prey,[15] and has been reported to exhibit "laying-on-side" death mimicry in a similar fashion to Parachromis friedrichsthalii and Nimbochromis livingstonii.[16][17] The species also has an absolute requirement for vitamin C and develops health problems in its absence.[18]
The species was originally described by Louis Agassiz in 1831 as Lobotes ocellatus, as he mistakenly believed the species was marine, latter work assigned the species to the genus Astronotus.[8] The species also has a number of junior synonyms: Acara compressus, Acara hyposticta, Astronotus ocellatus zebra and Astronotus orbiculatus.[19]
A. ocellatus are popular as pets, and are regarded as intelligent by aquarists. This is in part as they learn to associate their owners and food[6] and are purported to be able to distinguish their owner from strangers.[20]
Despite their large size, and predatory nature A. ocellatus are relatively placid aquarium residents best housed with other fishes too large to be considered food items.[5][6][20] They also get along with aggressive fish such as a convict cichlid.
A. ocellatus are known to uproot plants, and move other objects in aquariums[23] and are best maintained in volumes of 200-600 litre (75 or more gallons).[20][23] A. ocellatus is relatively tolerant of a range of typical aquarium water chemistries,[5] though its large size and messy feeding habits necessitates that efficient filtration be installed on the aquarium.[20] A. ocellatus is undemanding to feed in captivity and will accept a range of foods that include pieces of fish and prepared cichlid foods.[5][6][20] Oscars may also tend to jump out of an aquarium if the lid isn't supported sufficiently.
10/01/2008
Maylandia estherae (red zebra cichlid)
One of the well known Lake Malawi mbuna is Metriaclima estherae a rock dwelling cichlid from the east coast of Lake Malawi. These fish like, most cichlids from the lake, are 'mouthbrooders', females hold their fertilized eggs, then fry, in their mouth until they are released after about 21 days.
Females can grow up to 10cm (4 in) while males will grow up to 12.7 cm (5 in).
Aquarium Care
The males are territorial and subordinate males will be picked on by the dominant or alpha male. Like the other cichlids of this genus, are best kept in tanks harems with one male to many females. They prefer a rocky terrain providing numerous hiding places where weaker fish can find necessary shelter. Their predominate food source is algae though those in aquaria will take typical cichlid foods and some vegetable greens as a treat.
http://en.wikipedia.org/wiki/Maylandia_estherae
afra cichlid
The afra cichlid has an elongate body typically with vertical blue and black bars. However, there are many different colorations depending on the region the fish is from, for example, the male fish from Kobwe have greenish stripes on blue-black body. They can grow up to 10 cm. Like many other cichlid from Lake Malawi, afra cichlids are mouthbrooders. Males defend boulders as their territories and feed from algae on those boulders. Females congregate in mid-water and feed from plankton.
Like many mbuna cichlids, this is a notoriously aggressive fish that should be kept in a species or mbuna tank. The best practice is to keep one male with several females. They should be provided with large spaces with plenty of hiding shelters.
Electric yellow cichlid
Their bodies are strikingly bright yellow, with males having dark black streaks on their dorsal, pelvic, and ventral fins. While specimens kept by aquarists are generally bright yellow with black markings, specimens from different areas of Lake Malawi exhibit different coloring. In fact, their quality is determined mostly on appearance, with brighter yellow, less white, and minimal appearance of the bars along their broad side making a better cichlid. Males and females are sexually monomorphic with most males exhibiting black ventral fins and broader black dorsal stripe, though the best way to sex them would require examining their vents, while behaviour can provide reliable hints (females tend to be smaller and less aggressive). In their natural habitat, electric yellow grow to about 9 cm in length, and have been known to reach 15 cm in captivity.
This species is a mouthbrooder, meaning the larvae are carried, hatch, and develop in the mother’s mouth (buccal cavity), for about three weeks. These fish are ovophiles and the male will excavate a pit in the sand within his territory, in which the female lays the eggs; the female then takes these eggs into her mouth for fertilization.
Electric yellows come from a tropical climate and prefer freshwater with a pH between 7.8 and 8.9 and an ideal temperature range of 23–26 °C (73–78 °F). Spawning may be triggered by a drop in temperature which, in their natural habitat of Lake Malawi, usually indicates an influx of rain.
Aquarium care
Electric yellows are peaceful compared to most other African cichlids. Despite this, like all cichlids from Lake Malawi, they are best kept in specialist cichlid aquariums. As with most cichlids, electric yellows should not be kept with freshwater community aquarium species such as Zebra Danios or Neon Tetras, they may nip the finnage of other species, and are not recommended for freshwater community aquariums because of the differences in the natural habitats between cichlids and other fish species. In an aquarium setting, their natural habitat of rocks and caves should be emulated. Their diet should consist mostly of prepared cichlid pellets or flakes, supplemented with foods like krill, brineshrimp, Spirulina flake, and veggies. A healthy diet and carotene rich foods like krill and spirulina will help your fish, in good lighting, to appear neon-like (hence the name “electric yellow”).
http://en.wikipedia.org/wiki/Electric_yellow_cichlid
