Anecdotal field observations are reported for the first time for the genus Zenatr chopterus. In Z. buffonis, a species with only slightly modified male dorsal and anal fin rays, male and female swim in parallel, the male flicking the posterior body part against the female. In Z. gilli, a species with highly modified male dorsal and anal fin rays, the male swims alongside the female, folding the dorsal and anal fins in her direction, to cling to her. The function of the modified fins of male Zenarchopterus had not yet been explained, and we hypothesize that in some species with dramatic modifications, the dorsal and anal fin function as a clasping mechanism.