Five stages of maturity have been delineated forNoemacheilus triangularis Day. Progression of the mode in each stage of maturity has been traced from ova|diameter studies. The size at first maturity for male is around 44·5 mm and for female around 52 mm. Spawning is asynchronous and prolonged. There may be successive spawning during the year. Sexes are present in almost equal numbers. Fecundity is dependent on length and weight of fish and on length and weight of ovary.