Fluorescence in situ hybridization of 5S rDNA sequences to metaphasic chromosomes of Neotropical cichlids. The 5S rDNA sequences were detected with FITC (green), the chromosomes were counterstained with DAPI, and the images were converted to grayscale. (a) Retroculus lapidifer, (b) Astronotus ocellatus, (c) Cichla piquiti, (d) Geophagus proximus, (e) Satanoperca jurupari, (f) Aequidens tetramerus, (g) Laetacara dorsigera, (h) Heros efasciatus, (i) Mesonauta festivus. The arrowheads indicate the 5S rDNA-bearing chromosomes, and the asterisks mark the chromosomes bearing two sites. Bar = 5 μm.