Seahorses are a charismatic component of the fish fauna in estuarine and coastal marine water. In addition to their unique morphology and reproductive strategy, they are threatened by habitat degradation. The taxonomy of seahorses has been problematic with many species misidentified in museum collections. This poster will describe and compare differences in morphological characters of juveniles, such as the size, number and location of spines on the body and the structure of the coronet, on the head which are important features for identification of adults of different species. We will describe the morphology of newly hatched juveniles and ontogenetic changes with growth of three species of seahorses, Hippocampus whitei, H. abdominalis and H. breviceps from south-eastern Australia. The ontogenetic changes in morphology of juveniles of the three species will also be compared with the adult morphology of the three species.