algaeeating

Algaeeating, also referred to as algivory, is the feeding behavior by which organisms obtain nutrition by consuming algae. Algae encompasses a range of photosynthetic organisms, from microscopic phytoplankton and diatoms to larger forms such as filamentous and macroalgae. Algaeeating occurs across a broad array of taxa in both marine and freshwater environments, including herbivorous invertebrates, fishes, and some birds.

Ecological role and significance include regulation of algal populations, maintenance of clean and stable surfaces in aquatic systems, and contribution to energy flow within food webs. By removing algae, alga-eaters can influence nutrient cycling, light penetration, and community composition on rocks, reefs, and sediments. Their activity helps prevent excessive algal overgrowth that can smother other organisms or degrade habitat quality.

Feeding strategies vary by organism. Many alga-eaters graze on epilithic or periphytic algae that grow on hard surfaces, scraping biofilms off rocks, shells, and vegetation. Others feed on macroalgae, grazing within algal mats or gardens. Some groups specialize in particular algae, while others are generalists. A wide range of functional types contribute to algivory, from grazing gastropods and sea urchins to herbivorous reef fishes and certain crustaceans.

Human relevance includes applications in aquaculture and aquarium husbandry, where algivorous species are used to control unwanted algal growth. In ecology and conservation, understanding algivory helps explain reef resilience, freshwater ecosystem health, and responses to nutrient inputs and species introductions.