Live Feed

Live feed denotes the cultured or collected live prey organisms fed to fish and crustacean larvae during the first-feeding window, principally rotifers (Brachionus plicatilis and smaller B. rotundiformis strains, 90-250 micrometres) and brine shrimp Artemia nauplii (400-500 micrometres), and in marine hatcheries copepods are increasingly favoured for their superior nutritional profile and movement. First-feeding larvae of seabass, seabream, and most marine species do not accept dry feed, and their small mouths and undeveloped digestive systems require live prey that swims, triggers a hunting response, and is digestible; survival through first feeding largely determines hatchery output. Live feeds are nutritionally incomplete, especially in the omega-3 fatty acid DHA, so they must be enriched with emulsified oil or algae (Isochrysis, Nannochloropsis) for 6-24 hours before use, a practice called gut loading; enrichment quality directly transfers to larval growth and pigmentation. Production is labour- and space-intensive, with rotifer cultures requiring daily density monitoring (200-400 rotifers/mL is typical production density) and Artemia requiring cyst hatching, decapsulation, and rinsing. Copepod-based systems reduce reliance on enrichment and improve deformity rates but cost more to scale.