Astronotus ocellatus


Astronotus ocellatus
Oscar
奥斯卡

Common Oscar
普通奥斯卡

Albino Common Oscar
白化普通奥斯卡

Red Oscar
红奥斯卡

Albino Red Oscar
白化红奥斯卡

Tiger Oscar
老虎奥斯卡

Albino Tiger Oscar
白化老虎奥斯卡

Long Fin Common Oscar
长尾普通奥斯卡

:Long Fin Tiger Oscar
长尾老虎奥斯卡

Long Fin Albino Tiger Oscar
长尾白化老虎奥斯卡

Astronotus ocellatus is a species of fish from the cichlid family known under a variety of common names, including oscar, tiger oscar, velvet cichlid, or marble cichlid. In South America, where the species naturally resides, A. ocellatus specimens are often found for sale as a food fish in the local markets.The fish can also be found in other areas, including China, Australia, and the United States. Although its slow growth limits its potential for aquaculture, it is considered a popular aquarium fish.The species was originally described by Louis Agassiz in 1831 as Lobotes ocellatus, as he mistakenly believed the species was marine; later work assigned the species to the genus Astronotus.The species also has a number of junior synonyms: Acara compressus, Acara hyposticta, Astronotus ocellatus zebra, and Astronotus orbiculatus. A. ocellatus examples have been reported to grow to about 45 centimetres in length and 1.6 kilograms in weight. 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. These ocelli have been suggested to function to limit fin-nipping by piranha (Serrasalmus spp.), which co-occur with A. ocellatus in its natural environment. The species is also able to rapidly alter its colouration, a trait which facilitates ritualised territorial and combat behaviours amongst conspecifics. Juvenile oscars have a different colouration from adults, and are striped with white and orange wavy bands and have spotted heads.
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. In its natural environment, the species typically occurs in slow-moving white-water habitats, and has been observed sheltering under submerged branches. Feral populations also occur in China, northern Australia, and Florida, USA 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. Although the species is widely regarded as sexually monomorphic, males have been suggested to grow more quickly, and in some naturally occurring strains, males are noted to possess dark blotches on the base of the dorsal fin. The species reaches sexual maturity at approximately one year of age, and continues to reproduce for nine to ten years. Frequency and timing of spawning may be related to the occurrence of rain. A. ocellatus fish are biparental substrate spawners, though detailed information regarding their reproduction in the wild are scarce.

The closely related Astronotus crassipinnis has been observed, in times of danger, to store food in its mouth, possibly for protection, in a manner reminiscent of mouthbrooding geophagine cichlids. This behaviour, however, has not yet been observed in A. ocellatus. In captivity, pairs are known to select and clean generally flattened horizontal or vertical surfaces on which to lay their 1,000 to 3,000 eggs. Like most cichlids, A. ocellatus practices brood care, although the duration of brood care in the wild remains unknown. Captive oscars may be fed prepared fish food designed for large carnivorous fish, crayfish, worms, and insects such as flies or grasshoppers. They even eat small mice, and crickets are also good live food. Since these fish eat fruit in the wild, it can also be used as a type of food. Just about anything that fell into the water would be eaten by oscars. Live feeder fish can be given. Most fish eaten by A. ocellatus in the wild are relatively sedentary catfish, including Bunocephalus, Rineloricaria, and Ochmacanthus species. The species uses a suction mechanism to capture prey, and has been reported to exhibit "laying-on-side" death mimicry in a similar fashion to Parachromis friedrichsthalii and Nimbochromis livingstonii. The species also has an absolute requirement for vitamin C, and develops health problems in its absence. A number of ornamental varieties of A. ocellatus have been developed for the aquarium industry. These include forms with greater intensity and quantities of red marbling across the body, albino, leucistic, and xanthistic forms. A. ocellatus with marbled patches of red pigmentation are sold as red tiger oscars, while those strains with mainly red colouration of the flanks are frequently sold under the trade name of red oscars. 

地图鱼(Astronotus ocellatus),俗名猪仔鱼、尾星鱼,原产于南美的亚马逊河。分类隶属于硬骨鱼纲、真骨鱼总目、鲈形目、丽鱼科、背丽鱼属。
地图鱼属大型热带鱼,全长可达40cm。体型宽大,侧扁,呈长椭圆形,头大,嘴大。背鳍基部很长,起自胸鳍上方背部直达尾鳍基部,鳍条前部是锯齿状短硬棘,后部软鳍条较长,与臀鳍成对称状。腹鳍胸位,结端尖条形。尾鳍后缘圆形。体侧散布着不规则的金色斑块,间镶红色条纹,状似地图而得名,尾鳍基部有镶金边的红色圆环,闪闪发光,酷似夏夜的星星,故又叫尾星鱼。地图鱼根据身体色泽的不同,又可分为白地图、花地图、红板地图和连板地图等等。
地图鱼对水质要求不严格,在弱酸性、中性和微碱性水中都能正常生活,水温要求在22~25℃,喜食动物性活饵料,属肉食性凶猛鱼类,不宜和小型鱼类混养。地图鱼虽然体型粗大,但游泳快速,反应敏捷,捕食准确,食量较大,比较挑食,爱吃富含蛋白质的食物,如蚯蚓、小鱼、小虾、泥鳅等鲜活饵料,适宜在大型水族箱内饲养。
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