Previous research has shown that larval redeye tetra Moenkhausia sanctaefilomenae have large craniofacial skeletons compared to equivalent zebrafish Danio rerio. In order to understand the further development of the craniofacial region, the development of the craniofacial musculature in both species were examined at different stages using whole mount immunohistochemistry. In addition, Alcian blue staining was used to observe their craniofacial cartilage to better understand the anatomy and identify the individual muscles. Unexpectedly, the muscle development was found to be more robust and intense in three day old D. rerio compared to equivalent M. sanctaefilomenae specimens. Differences were also observed in regard to the temporal and spatial patterns of muscle formation between the two species. Owing to their larger craniofacial skeletons, it was expected that M. sanctaefilomenae would likewise exhibit larger muscle corresponding with their large skeleton development. However, it was seen that the muscle development does not seem to coincide with the skeletal development
