Fish inhabiting shallow water are exposed to periodical changes in tidal cues including hydrostatic pressure (HP) and Some wrasse speacies which spawn synchronously with high tide preference during the spawning season. The present study aimed to perform transcriptome analysis in the brain of the threespot wrasse Halichoeres trimaculatus (tropical species) which were exposed to HP at 30 kPa (possible high tide stimuli in field) or 1 kPa (low tide) for 3-hour. This study will provide new insights into candidate genes that related tidal spawning rhythms in wrasse. which tidal related