Comparative scanning electron microscope studies have been performed on the skin of two oviparous and two viviparous freshwater fish embryos and larvae in order to investigate eventual morphological differences. In the early larval stages, temporary microvilli‐like structures (MVLS) were detected in oviparous fish larvae which were later replaced by raicroridge formations. In viviparous fish larvae, only‘fingerprint‐like’pattern microridge formations were observed. Light microscope slides showed that the disappearance of these MVLS were found to be chronologically related with the development of functional gill lamellae and yolk sac res