show Abstracthide AbstractSiamese fighting fish Betta splendens are notorious for their aggressiveness and males of this fish have been widely used to study aggression. However, an understanding of brain transcriptome signature associated with aggression in the context of male-male interaction in this fish remains to be understood. Herein, RNA-Seq transcriptome data from 12 brains samples collected at different fighting stages after fighting (A0 & A30) is described. These data provide resources for the study of aggressive behavior at molecular in fish.