Astronotus ocellatus
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Astronotus ocellatus

Common Names: Oscar
Synonyms: Lobotes ocellatus
Family: Cichlidae
Category: Cichlids
Distribution: America - South; Amazon River, South America.
Main Ecosystem: River; River
Temperament: Territorial; The temperament of oscars varies from individual to individual, and their territoriality varies from brusque to downright vicious. Small fish will simply be eaten. Gentle giants in this species area comparative rarity. Males can be particularly dominant and their territorial area is measured in feet rather than inches so any tank up to 200 gallon may be completely policed for the presence of other fish, irrelevant of species.

Oscars can fight with persistance and will liplock with other cichlid species. Their jaws are powerful and smaller fish such as angels and cichlids under 6 inches long are commonly exterminated by persistant fin nipping and outright bites complete with vicious shakes. In aggressive communities oscars either dominate or show their fragile side, and sometimes wane and fail to feed, rarely is perfect standoff and desired neutrality achieved. Success will be most likely with large catfish and non-cichlid species with heavy body armour, and a non-combatative personality in the largest tanks.

Compatible pairing works well, but introductions must be carefully monitored, and a tank seperator may prove to be an essential piece of equipment. Should pairs take off and breed, they may eliminate all other fish from the tank. Several crowded specimens will usually lead to one fish dominating, and sublimating and therefore eventually killing up to 6 other individuals.Do not buy too many oscars, just because they may be comparitively cheap. Many individuals will be better kept as single specimens in a large 120 gal plus tank, they can be personable and amusing to the keeper if not other fish, and this is where their appeal truly lies. Leave community settings and breeding efforts to the experienced, practiced, and proffessional.Correctly reading, pre-empting, and catering for the temperament of individual fish is an essential part of this species care
Diet: Carnivore; The avoidance of nutritional deficiency is essential for the long term maintenance and avoidance of hexamita susceptibility in this species. Offer a range of food with frequency and make every effort to avoid a monotypic diet. Offer whole, very fresh fish (prekilled is fine, live feedings are not usually required, although people often choose to provide them - it should be noted that many oscars pick up hexamita intestinalis from carrier goldfish)),also gamma irradiated fish for safety, pieces of worms,mollusc and shellfish meat, shrimp portions, occassionally beefheart,and try to choose a good cichlid staple food and include it as a permanent part of the diet.Carnivore pellets will also be accepted. Fish vitamins are a viable option for this species. Juveniles will also consider various midge larvae, and brineshrimp, and although they can be offerred to adults, some adults may prefer the meatier foods. Basically try any and all foods that have a primarily meaty base, and change and rotate foods often. Its perfectly acceptable to offer oscars a range of foods in one feeding. Dont rely on any one brand, formula or diet, and do not exclusively rely on dry,fresh, or frozen foods either. Use everything.
Care: Oscars are destructive fish, and will generally destroy plants unless very tough with strog roots, or an alternatve is to keep them potted. Most oscar setups will be bare by necessity aside from large chunks of rock (ph neutral , avoid limestones) bogwood, mopanietc. This is a powerful fish and a noted mover of cage decor so some rocks etc, may need to be either too large to move or siliconed and tied in place to prevent tank breakages. Oscars require roomy aquaria, they are a large mobile fish, and generally deserve at least 125-200 gallon quarters. Being a large predator these fish vent a lot of profoundly thick and protien rich waste and to avoid the legacy of ammonia and nitrite spikes, water changes will have to be sizeable, regular, and spot cleaning performed regularly. Oscars are a high maintenance species. Overfilter rather than underfilter, and prefilters will help to avoid waste purges blocking filters. Oscars are not a fish for the beginner, thir size , fast growth, aggression, and susceptibility to hexamita means they should be taken on only by the experienced and well funded keeper.
6 - 8
22°C - 27°C
72°F - 81°F
5 dH - 20 dH
Potential Size: Male: 35cm (13.8")
Female: 35cm (13.8")
Water Region: All; All
Activity: Diurnal; Diurnal
Gender: Not easily distinguishable. Sex can be determined by examination of the mature oscar's vent. Females have a more rounded 'appendage' then the males (of course this information is useless unless you have two fish of the opposite sex to compare). Females grow smaller than their male counterparts.
Breeding: Use a higher temperature of up to 29°C. Only use fish over 15cm. Place a large rock in the tank for the Oscars to breed on. The eggs are laid on the carefully cleaned rock. There is good parental care, of the eggs and the newly hatched fry. The parents will move the wigglers to a pit to guard them, and continue care after they become free swimming.
Variants: Oscars come in a variety of colours: Albino; Red; Blood Red; Tiger, Gold; or a combination of these. Long-finned, or veil-tailed, oscars are also available.
Comments: Oscars, like most other large cichlids, can be very susceptible to Hole in the Head (HITH) disease. The best way to avoid HITH is to maintain a strict quarantine of two months, feed a varied diet of good quality prepared and live foods and maintain good water quality to keep the immune system high. The use of UV sterilisation will act as a significant preventative, and stop much of the cycle of reinfestation that can occur with already afflicted fish, it will also help reduce incidences of transmission from one fish to another. Excellent filtration is a must and as are large partial water changes, preferably on a weekly basis.
Main Colours: Black, Brown, Orange
Markings: Mottled
Mouth: Normal
Tail: Convex
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Submitted By: Adam
Contributors: Jason_R_S, longhairedgit
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