 In female specimens, this consists of a fine black line, appearing almost as if drawn onto the fin with a fine pencil.In male specimens, particularly alpha males, the border is conspicuously wider, and in breeding alpha males, can cover up to a third of the total area of the anal fin.This is the only "reliable" means of differentiating gender in this species - while males frequently have taller and more pointed dorsal fins, some females also possess tall, pointed dorsal fins, and thus this characteristic is not reliable.