Distributions of fibronectin, microtubules and microfilaments in the melanophore of the medaka, Oryzias latipes, were studied using im-munofluorescence. We found fluorescent fibers of fibronectin running from the central region to the periphery of the melanophore, but patterns differed depending on whether melanophores had been treated with methanol. Fi-brous structures were present in methanol-treated melanophores, whereas only diffuse fluorescence was seen in untreated ones. These fibrous structures, thought to be microtubules, were arranged radially. Actin fibers also showed a radial arrangement, but were not as well organized. In addition, granules with actin immunofluorescence were present.