Nowadays image processing algorithms are widely used in tracking position and posture estimation of animals; for those who study neurophysiology, the automated analysis of recorded videos allows to associate a specific behavior with cerebral activity. The principal purpose is to avoid long tiring observation times and human errors in the validation of the recording. For aquatic animals like crayfish, developing a system that can track position and estimate posture is crucial, as water introduces image distortion. Crayfish is a good model that allows to study behaviors like aggressiveness, sleep and exploration. Developing a computer vision system that detects the position in the aquarium and if the crayfish is lying on one side described as the stereotypical sleep position, will help the observer to just analyze specific moments of the recording to take a decision. The results presented in this work show that it’s possible to use image processing to determine the position of a crayfish in the aquarium and to establish when the animal is lying on one side, allowing us to plot a graphic that represents the coordinates of position and the “sleep coordinates”, those moments when the crayfish was lying on one side, i.e., a whole hypnogram, in a non-supervised way.