aquafeed

Aquafeed is manufactured feed formulated specifically for farmed aquatic animals, primarily fish and crustaceans. Unlike terrestrial animal feeds, aquafeed must account for the aquatic environment: it must sink or suspend at the correct rate, resist water leaching, and deliver nutrition in a form the target species will actually consume. The feed sits in water for minutes to hours before being eaten, so particle integrity and palatability are critical to reducing waste and maintaining farm productivity.

Most aquafeed comes as pellets, ranging from 0.5 mm to 12 mm diameter depending on the species and life stage. Juvenile fish eat smaller pellets; larger carnivorous species like salmon or sea bass require bigger sizes. Formulation varies enormously: feeds for herbivorous carp differ radically from feeds for carnivorous trout or shrimp. Protein content typically ranges from 35 percent to 55 percent; carnivorous species demand higher levels. Fat, ash, fiber, and vitamin and mineral profiles are tuned to each species' known nutritional requirements, often based on research conducted on wild ancestors.

Materials and manufacturing

Aquafeed is produced by mixing fishmeal, soybean meal, grains, oils, and micronutrient premixes, then extruding or pelleting the blend. The extrusion process heats the mixture under pressure, which both binds particles together and partially cooks the ingredients, improving digestibility. Some feeds are cold-pressed to reduce nutritional losses from heat exposure. The finished pellet's density determines whether it floats, sinks slowly, or drops quickly to the bottom, a property critical for the feeding behavior of the target species.

Cost and sustainability are driving reformulation across the industry. Traditional aquafeed relied heavily on fishmeal and fish oil derived from wild-caught forage fish, a practice that raised ecological concerns. Modern formulations increasingly substitute plant-based proteins, algal oils, and insect meals. These alternatives require careful balancing to prevent nutrient deficiencies, particularly in amino acid profiles and long-chain omega-3 fatty acids, which farmed fish cannot synthesize themselves.

In practice, overfeeding with aquafeed is one of the most common and costly mistakes on aquaculture operations. Uneaten pellets sink and decompose, fouling water quality and requiring additional aeration or water exchange. Feed conversion ratio, the weight of feed needed to produce one kilogram of growth, is a key economic metric; typical ratios range from 1.2:1 for herbivorous tilapia to 2:1 or worse for carnivorous species. Automated feeders, often tied to sensors or timers, help operators optimize feeding rates and reduce waste.