Sudis gigas.

Arapaima gigas - anatomie
Date 1829
Source/Photographer Spix, Selecta genera et species piscium, quos in itinere per Brasiliam annos 1817-1820, tab. B
Old Latin name Arapaima gigas
New Latin name Arapaima gigas
Common name Nederlands: Arapaima
Source: https://commons.wikimedia.org/wiki/File:Arapaima_gigas_-_anatomie_-_1829_-_Print_-_Iconographia_Zoologica_-_Special_Collections_University_of_Amsterdam_-_UBA01_IZ15000202.tif

The pirarucu or giant arapaima (Arapaima gigas) is a species of arapaima native to the basin of the Amazon River. It is among the largest freshwater fish. Arapaima gigas is an obligate air-breather and needs to come to the surface regularly to gulp air.