This study examined the effects of dietary supplementation with selected plant extracts on the haematology, enzymatic activities, and growth of Pangasianodon hypophthalmus fingerlings. A 60-day feeding trial was conducted with 11 diets: basal diet (basal diet); and basal diet supplemented with 0.4% or 2% Euphorbia hirta (Eh), 0.2% or 1% Phyllanthus amarus (Pa), 0.4% or 2% Mimosa pudica (Mp), 0.2% or 1% Psidium guajava (Pg), and 0.4% or 2% Azadirachta indica (Ai). On days 30 and 60, the haematocrit improved significantly in response to the Pg 0.2 diet (35.9±0.8% and 36.4±0.7%, respectively), while the haemoglobin level increased significantly in fish fed a diet with Mp or Pg at both concentrations. Chymotrypsin activity was highest (121±6.10 U min-1 mg-1 protein) under the Pa 0.2 diet followed by the Eh 0.4 and Pa 1.0 diets (94.1±7.20 and 92.2±7.80 U min-1 mg-1 protein, respectively) on day 30. The Pa 0.2 diet significantly enhanced chymotrypsin activity on day 60 compared to the other diets. Fish fed the Pa 0.2, Pa 1.0, or Pg 1.0 diet showed significantly increased pepsin activity than those fed the control diet on day 30, whereas there was not observed significant difference on day 60. Amylase activity was significantly enhanced in response to the Eh 0.4, Pa 0.2, Pg 0.2, and Ai 0.4 diets, but none of the diets led to a change in trypsin. Sixty days of oral administration of Pg 0.2 or Pa 0.2 extracts modulated haematological parameters and digestive enzyme activities of P. hypophthalmus fingerlings and resulted in higher growth performance.