The results of the Cytogenetic studies carried out in two marine ornamental fishes, Chaetodon collare and Stegastes insularis, occurring in the south-eastern Arabian Sea, by Giemsa staining and nuckolar organizer regions (Ag-NOR) staining are reported. The diploid chromosome number (2n) in C. collare and S. insularis was found to be 48. Based on the karyomorphology, the karyotype formula was derived as 48t (FN=48) and 14m + 24 sm + 6st + 4 t (FN=86), respectively for these two species. Silver staining revealed presence of one pair of NORs in both the species. This is the first description of karyotypes in these species using conventional staining and chromosome banding techniques.