Pirarucu ( Arapaima )

The arapaima, pirarucu, or paiche (Arapaima) is a genus of bonytongue native to the Amazon River in Brazil.
They are the largest freshwater fish of South America Arapaima can reach lengths of more than 2 m (6 ft 7 in), in some exceptional cases even more than 2.5 m (8 ft 2 in) and over 100 kg (220 lb).
The maximum recorded weight for the species is 200 kg (440 lb), while the longest recorded length was 4.52m(15 feet).
As one of the most sought after food fish species in South America, it is often captured primarily by handheld nets for export, by spearfishing for local consumption, and consequently, large arapaima of more than 2 m (6 ft 7 in) are seldom found in the wild today.
The arapaima is torpedo-shaped with large blackish-green scales and red markings. It is streamlined and sleek, with its dorsal and anal fin set back near its tail. Its local name, paiche, derives from the indigenous words for "red" and "fish".
Arapaima gigas scales[3] have a highly mineralised, very hard outer layer with a corrugated surface under which lie several layers consisting of collagen fibres. In a structure similar to 'plywood', the fibres in each successive layer are oriented at right angles to that in the previous layer for maximum toughness.
The hard corrugated surface of the outer layer, the soft but tough internal orthogonal collagen layers and the hydration of the scales all contribute to their ability to flex and deform while remaining strong—a solution that allows the fish to remain mobile while heavily armoured and enables it to live in piranha-infested lakes, where no other animals could survive.
The arapaima has a fundamental dependence on surface air to breathe.
In addition to gills, it has a modified and enlarged swim bladder, composed of lung-like tissue, which enables it to extract oxygen from the air.
This is an adaptation to the often hypoxic conditions of the Amazon floodplains, but requires the arapaima to surface for air every 5 to 15 minutes.
This tendency to stay at the surface makes it more vulnerable to attacks from spear fishermen.

Its The Some Image Of Pirarucu