Investigating olfactory behaviors in adult zebrafish

Odor-driven behaviors such as feeding, mating and predator avoidance are crucial for animal survival. While the zebrafish olfactory circuitry is well understood, a comprehensive description of odor-driven behaviors is needed to better relate olfactory computations to animal responses. Here, we used a medium-throughput setup to measure the swimming trajectories of 10 zebrafish in response to 17 ecologically relevant odors. By selecting appropriate locomotor metrics, we constructed ethograms systematically describing odor-induced changes in the swimming trajectory. We found that fish reacted to most odorants, using different behavioral programs and that combination of few relevant behavioral metrics enabled to capture most of the variance in these innate odor responses. We observed that monomolecular odors in similar chemical categories were weakly clustered based on the behavioral responses, likely because natural odors elicited stronger reactions than the monomolecular odors. Finally, we uncovered a previously undescribed intra and inter-individual variability of olfactory behaviors and suggest a small set of odors that elicit robust responses. In conclusion, our setup and results will be useful resources for future studies interested in characterizing olfactory responses in aquatic animals.