This study was undertaken to characterise the effect of endocrine disrupting chemicals (EDCs) on aromatases in a model fish species, the zebrafish. We first developed methods to measure brain and gonadal aromatases at mRNA, protein and enzymatic levels and characterised the baseline expression in adult and larvae control fish. We further determined that (xeno)-estrogens induced cyp19b gene expression in the brain while they inhibited cyp19a expression in the ovary. TCDD, an aryl hydrocarbon receptor agonist, presented anti-estrogenic effects on the estradiol-dependent induction of cyp19b gene expression. Androstatrienedione, a steroidal aromatase inhibitor and clotrimazole, a fungicide known to inhibit aromatase activity in vitro, were able to perturb aromatase expression in vivo, but in a more complex fashion than expected based on in vitro data. Our work showed that fish aromatases are molecular and biochemical targets of EDCs belonging to diverse chemical classes (xeno-estrogens, dioxins, pesticides). Overall, we provide new and relevant data on the effects and mechanisms of action of EDCs in fish, which raises the question of the physiological consequences of such aromatase perturbation for the organism.