Gulf pipefish (Syngnathus scovelli) exhibit sex-role-reversal with females possessing iridescent bands that are absent in males as well as a deeper body. We took advantage of the fact that males develop the female-typical traits of bands and deeper bodies after exposure to estrogen. We sampled the skin and muscle tissue around the bands in females, females exposed to estrogen, and males exposed to estrogen, as well as skin and muscle tissue in males that lacked a banding pattern. Using the transcripts from the tissues in these four groups we aimed to identify genes associated with maintenance and development of the female secondary sex traits of bands and deeper bodies. We compared expression patterns of control males to those of estrogen-exposed males, estrogen-exposed females, and control females.