When Bryconaethiops boulengeri enters breeding condition, the males undergo a remarkable transformation and their silvery appearance gives way to a much darker coloration, while an intense deep-red sheen gradually spreads across the body and fins. Females, in contrast, retain their characteristic silvery-yellow colouration and show little visible change.
At this stage, the dominant males become increasingly territorial: they will actively defend small sections of the aquarium and react aggressively towards rival males, engaging in impressive display behaviour, fin spreading, and short chases. Watching these interactions unfold is a fascinating experience and provides a glimpse into the complex social dynamics of this species.
Few African characins combine such striking colour changes with such lively behaviour. Bryconaethiops boulengeri is truly a spectacular fish and a constant source of enjoyment in the aquarium. - Michael Keijman
