Zooplankton biomasses are essential nutritional sources for early-stage aquatic organisms due to their high-value nutrient profiles. Recent studies highlight the potential of zooplankton mixtures and Artemia franciscana (Leach, 1819) biomasses as protein-rich alternatives for fish diets. The current study analyzed these biomasses for chemical composition, vitamin content, and antioxidant properties. For the first time, a zooplankton mixture was evaluated for its antimicrobial, anti-biofilm, and anticancer activities against various pathogenic microorganisms and cancer cell lines. Antimicrobial assays demonstrated that both the zooplankton mixture and A. franciscana biomass exhibited inhibitory effects against Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 27853, and Alternaria solani RCMB 009 003, as observed through agar well diffusion. Anti-biofilm testing showed that the biomass of the zooplankton mixture effectively inhibited biofilm formation by P. aeruginosa ATCC 27853 and S. aureus ATCC 6538. Additionally, anticancer activity was assessed against three cancer cell lines: breast (MCF-7), liver (HepG-2), and colon (HCT-116). The zooplankton mixture and A. franciscana biomass displayed cytotoxicity across all cell lines, with IC50 values for HepG-2 at 23.47 μg mL􀀀 1 and 14.48 μg mL􀀀 1, respectively; for HCT-116 at 19.46 μg mL􀀀 1 and 13.05 μg mL􀀀 1, respectively; and for MCF-7 at 26.51 μg mL􀀀 1 and 16.81 μg mL􀀀 1, respectively. These findings suggest that both biomasses are promising candidates in medical applications, with potential antimicrobial and anticancer effects.