show Abstracthide AbstractTambaqui (Colossoma macropomum Cuvier, 1818) is an endemic fish species of the Amazon and Orinoco basins and an economically important species for brazilian aquaculture. Captive tambaqui are raised in five climatically distinct regions, with an average annual temperature difference ranging up to 14 °C between northern and southern cities of Brazil. Herein we used two farmed tambaqui populations from northern (Balbina Experimental Station, Balbina, Amazonas state) and southeast (Brumado Fish Farming, Mogi Mirim, São Paulo state) to describe the molecular mechanisms for thermal adaptation. Twelve cDNA libraries from liver of juvenile tambaqui were constructed, with three biological replicates of each population. RNA was sequenced (RNA-Seq) on the MiSeq® Platform (Illumina®).