<p>An eight-week experiment was conducted to evaluate the impacts of stocking density on growth indices, hematological changes, physio-immunological parameters, as well as digestive and anti-oxidative activities of <i>Macrobrachium nipponense</i>. Prawns with a mean initial weight of 1.40 ± 0.09&#xa0;g were randomly assigned to four different stocking density groups, each with three replicates. The groups corresponded to stocking densities of 15 (D₁₅), 20 (D₂₀), 25 (D₂₅), and 30 (D₃₀) individuals. The findings reveal significant effects of stocking densities on water quality parameters (<i>P</i> &lt; 0.05), while temperature remained stable (<i>P</i> &gt; 0.05). Stocking densities significantly influenced growth performance, with D₂₅ achieving superior metrics compared to D₃₀, which exhibited the lowest growth indices (<i>P</i> &lt; 0.05). Most hematological parameters significantly decreased as stocking density increased up to the D₂₅ treatment, whereas high-density lipoprotein (HDL) and low-density lipoprotein (LDL) levels significantly increased (<i>P</i> &lt; 0.05). Furthermore, immunological responses showed significant improvement with increasing stocking density up to D₂₅ (<i>P</i> &lt; 0.05). The antioxidant status was significantly enhanced in the D₂₅ treatment (<i>P</i> &lt; 0.05). The activities of digestive enzymes were highest in the D₂₅ treatment (<i>P</i> &lt; 0.05). As the stocking density increased to D₂₅, carcass moisture significantly decreased, while protein and lipid content markedly increased, with minimal levels of protein and lipid observed in D₃₀ (<i>P</i> &lt; 0.05). In conclusion, the D₂₅ stocking density treatment improves various parameters in <i>M. nipponense</i>. Therefore, the D₂₅ stocking density is recommended for optimal aquaculture practices for this species.</p> Graphical Abstract <p></p>