post-embryonic appendage morphogenesis post-embryonic medial fin morphogenesis The process, occurring after embryonic development, by which the anatomical structures of the medial fin are generated and organized. Medial fins are unpaired fins of fish, usually located dorsomedially or ventromedially and primarily used for stability while swimming. post-embryonic unpaired fin morphogenesis biological_process GO:0035132 medial fin morphogenesis