To further understand the physiological mechanism of growth of different mandarin fish, the relationship between growth rates and daily food intake, pepsin activities, relative expression of pepsinogen PGA1, PGA2, PGC in stomach of juveniles of S. chuatsi, S. scherzeri and their hybrids (S. scherzeri ♀×S. chuatsi ♂ F₁) were compared and analyzed during 30 days' experiment. Results showed that average growth weight (AGW) of three species was (1.171± 0.180) g/d of S. chuatsi, (1.019± 0.104) g/d of hybrids, (0.433± 0.078) g/d of S. scherzeri, respectively, and their growth rates ranked as S. chuatsi > F₁> S. scherzeri. Daily food intake of the three species was (6.1±0.31) g/d of S. chuatsi, (4.24±0.23) g/d of S. scherzeri and (5.26±0.33) g/d of hybrids, respectively, S. chuatsi was higher than hybrids and S. scherzeri. The maximum specific pepsin activity was found in stomach, specific pepsin of the three species was (347.8±13.3) U/g of S. chuatsi, (272.1±10.9) U/g of S. scherzeri (303.4±12.1) U/g of hybrids during later periods. Among the three species, pepsin activities ranked as S. chuatsi > F₁ >S. scherzeri. Gastric PGs mRNA expression of three species all increased during the experiment. Proportion of PGC: PGA1: PGA2 was 1.1:1.0:0.7.The highest expression level of PGs was observed in S. chuatsi, PGs expression of F₁ was slightly higher than S. scherzeri (P<0.05). Growth rate was in direct correlation with amount of food intake of the three Siniperca species, and there was a corresponding relationship between amount of food intake and digestive capacity.