Hydrolycus armatus
The Hydrolycus armatus naturally inhabits the Amazon and Orinoco rivers in South America. The fish lives in swift currents, in turbulent water near rapids. This fish belongs to the largest predators living in South American rivers. They require a very large aquarium, so they are not found in many aquarists' home collections.
Hydrolycus armatus have an elongated silver-coloured body, tapering closer to the base of the tail. The head is large, and the entire mouth is studded with teeth as sharp as knife blades. Adult fish have two large fangs on the lower jaw that run through the openings on the upper jaw. Under natural conditions, these fish reach up to a meter in length, while in aquariums they are usually no larger than 60 cm. The weight of adult fish sometimes exceeds 10 kg.
The Hydrolycus armatus is an undemanding fish. Should be kept in a 2000 litre aquarium. No requirements for the interior arrangement of the aquarium, because these fish feel comfortable even in a completely unequipped aquarium.
These fish are very aggressive, especially towards structurally similar fish. You should therefore keep Hydrolycus armatus singly or together with larger bottom feeders. Stable water conditions are required. They should not be kept in an aquarium in which biological equilibrium has not yet been established. The aquarium should always be covered from above, as pajars are excellent jumpers. By and large, maintaining proper water quality requires the use of expensive water filters, so the content Hydrolycus armatus can not afford not all aquarists.
Water parameters: temperature 24 - 28° C, hardness dH 5-15°, pH 6,0-8,0. Need strong aeration of water, good filtration and a weekly change of ½ of the aquarium water with fresh. Create a moderate water flow in the aquarium with a water pump.
The fish's menu in the wild consists mainly of piranhas, with the paira being able to swallow prey that reaches half its own size. Newly imported individuals often refuse to eat anything other than live fish, but they can be accustomed to frozen fish meat over time.
Like the vast majority of predatory fish, this species should not be fed with poultry or mammal meat such as beef heart or chicken. Young fish are fed with earthworms and shrimps.
Reproduction
The Hydrolycus armatus does not breed under aquarium conditions. In nature, fish spawn in November and April, going upstream to the mouths of rivers for this purpose.
The life expectancy of the pajara under aquarium conditions is about 2 years.
