Background - Traditional fishing communities are strongholds of ethnobiological knowledge but establishing to what degree they harbor cultural consensus about different aspects of this knowledge has been a challenge in many ethnobiological studies. Methods - We conducted an ethnobiological study in an artisanal fishing community in northeast Brazil, where we interviewed 91 community members of different genders and dedicated to distinct activities, in order to obtain free lists and salience indices of the fish they know. To establish whether there is cultural consensus in their traditional knowledge on fish, we engaged a smaller subset of 45 participants in triad tasks where they chose the most different fish out of 30 triads. We used the similarity matrices generated from the task results to detect if there is cultural consensus in the way fish were classified by them. We also modelled the effect of gender, age and type of activity on the agreement rate of participants with modal responses in the triad tasks (i.e., that pair of fish in which most participants considered the most similar within each triad).Results - The findings show how large is the community’s knowledge of fish, with 197 ethnospecies registered, of which 33 species were detected as salient or important to the community. In general, men cited more fish than women. We also found that there was no cultural consensus in the ways fish were classified, but younger participants tended to use similar criteria for classifying fish. Conclusions - Both free-listing and triad task methods revealed little cultural consensus in the way knowledge is structured and how fish were classified by community members. Our results suggest that it is prudent not to make assumptions that a given traditional community has a single cultural consensus model in classifying the organisms in their environment.