This study successfully determined the chromosome numbers and karyotypes of two marine fish species from separate families using the short-term culture method (PB-MAX™ application). The culture incubation periods varied for each species. Kidney tissues from the fish samples were treated with PB-MAX™ for either 2.5 or 4 h. Results showed that diploid chromosome numbers, karyotypes, and arm numbers differ by species: Red Mullet, Mullus barbatus, has 2n – 44, with 3 pairs of metacentric, 7 pairs of submetacentric, 7 pairs of subtelocentric, and 5 pairs of acrocentric chromosomes (NF=64). Round Goby, Neogobius melanostomus, has 2n – 46, consisting of 46 pairs of acrocentric chromosomes (NF=46). C– and NOR–positive results were achieved through constitutive heterochromatin banding and silver nitrate staining for both species. The primary objective of this research is to demonstrate the applicability of short-term culture in producing successful cytogenetic results in marine fish. This study will support future research and facilitate chromosome studies on marine fish, making the process quick and practical.