a procedure that uses a silver stain that preferentially accumulates in the nucleoli-organizing regions, that is, the satellite regions of the acrocentric chromosomes.
Almeida-Toledo and Foresti (1985) studied the NOR-banding pattern in 48 fish species of the Anostomidae, Sternopygidae, Parodontidae, Characidae and Cichlidae families, and found only one mark in all species.