This paper reviews the main results of 4 years studies on the reproductive behaviour of Barbus barbus (L., 1758) and Barbus meridionalis (Risso, 1826) under controlled conditions in aquarium. The reproductive behaviour is described as well as the behavioural mechanisms of hybridization. During the spawning act - sometimes preceded by > in which two fish swim together, at high speed, head against head the female and the few accompanying males rise from the gravel and move their genital papilla in the gravel while releasing ova or sperm (fig. 1 and 2). The reproductive behaviours of Barbus barbus and Barbus meridionalis appear to be similar and hybridizations were observed, showing that no complete behavioural barrier blocks the mating of the two species (fig. 2). The daily rhythms of activity are compared within the two species. The influence of temperature and daylength on the daily rhythms of activity is discussed. in winter conditions, barbels exhibit a night activity rhythm. Spawning occurs during daytime or during the night (fig. 3). The influence of spawning stimuli is analysed using dummies of different sizes and colors (photo I). Barbels seem to prefer white, grey, yellow and brown colors to red or black colors.