It can be relatively challenging to distinguish male from female Mascara barbs as both sexes will show impressive red colouration as mature adults. However, males will typically have a more intense colour pattern and develop detailed dorsal filaments and vivid red dorsal fins and, when in breeding condition, will display noticeable tubercules on their heads. In contrast, adult females usually grow a little larger, are heavier-bodied, and less colourful than males.