In this study, some biological characteristics of Planliza abu were investigated using 460 specimens (221 female, 207 male and 32 unidentified) collected from Karun River, Khuzestan province from October 2016 until September 2017. Sampling process was conducted by local fishermen using Trawl net. Total length of females and males ranged from 10 to 17.1 cm (13.16± 1.26 SD) and 10.5 to 17.3cm (13.44±1.35 SD), respectively. The age of specimens ranged between 0 + to 7 + . The most frequent age group were 4 + in males and females. Sex ratio was 1:1.06 (M:F). Among all examined stomach 214 were empty (vacuity index, Vi=46.52%). This variation was significantly different (p 0.05) over the year and the maximum number of empty stomachs was recorded during spring and the minimum during the autumn. Relative length of gut ranged between 1.21 to 3.21 with an average of 2.27±0.36 showing this specimen as omnivores. The highest value of condition factor was observed in July for both sexes. The length-weight relationship was described as W=0.0268L 2.722 , (r 2 =0.9118) for males, W=0.0338L 2.637 , (r 2 =0.8816) for females and W=0.0296L 2.686 , (r 2 =0.9054) for all samples. This relationship showed that the growth was negative allometric for males and isometric for females. The von Bertalanffy growth models were estimated as L t =11.90[1-e 0.21(t-2.26) ] and L t =13.45[1-e 0.66(t-39.63) ] for males and females, respectively. The growth performance indices were estimated as 3.39 for males and 4.79 for females, indicating a faster growth rate for female individuals. Oocyte diameters ranged from 0.12 to 0.57 mm. Absolute fecundity ranged between 3600 and 48600 eggs. Relative fecundity ranged between 120 and 900 eggs/Kg body weight. Changes in hepatosomatic index (HIS) in females during vitellogenesis in breeding seasons were high and its highest value was in February (1.89). According to gonadosomatic index (GSI), egg diameter, monthly distribution of different stages of ovarian maturation, it was determined that the spawning peak is in February (average GSI 12.35) and March (average GSI 12.18). The long spawning season indicated that this fish has group synchronous ovaries. Keywords : Growth, Reproduction characteristic, Nutrition, Fecundity, von Bertalanffy