<p>Color polymorphism is widespread among invertebrates. Amphipods exemplify this through discrete pigmentation morphs within populations. However, differences in physiological and biochemical parameters between morphs remain largely unexplored in these crustaceans. In the present study, we compared catalase activity, hemocyte count, glucose and protein content across <i>Dikerogammarus villosus</i> (Sowinsk) coy, 1894lor morphs: spotted (S), melanic (M), striped with wide pigment bands (B1) and thin pigment bands (B2). While no sex-based differences occurred in comparable-sized individuals, some biochemical parameters varied selectively across morphs. Total protein content exhibited significant inter-morph differences, exceeding 1.5-fold contrasts between specific variants, while glucose concentrations also showed highly significant variation across morphs, differing by over 1.5-fold, indicating divergent energy allocation strategies and metabolic specialization. While no overall difference occurred in total hemocyte counts, pairwise comparisons revealed near 1.8-fold disparities between specific morphs. In contrast, catalase activity remained uniform across all morphs. In our study, we found that the pigmentation morphs of the amphipod <i>D. villosus</i> have differences in some physiological and biochemical parameters. This is the first description of this phenomenon for amphipods. This work creates a foundation for further in-depth research on the genetics of this species and determination of the differences between morphs in physiological and biochemical parameters.</p>