Remove the other fish if they are apt to be fin nipped. Do not feed the barbs, and they will hopefully clear out the hair algae. Sexing Sexing is very easy. The males are mostly a deep red while the females are a deep yellow. In overcrowded or dirty tanks where the fish become sick, the males lose their color.
Females are often the smaller of the pair and wider.
Sometimes, one can see what looks like an ovipositor protruding from her vent. Unless a breeding setup is provided, they will most likely eat all the eggs and fry. If you add them to a shallow container with their water and marbles or coarse gravel on the bottom, any eggs laid should be out of reach. Provide soft plants for her to be pushed against. The eggs will fall into the substrate.