Abstract
Natural food webs in freshwater pond ecosystems provide an important nutritional foundation for cyprinid aquaculture, yet information on their protein and amino acid composition remains fragmented. This review synthesized published data from 30 studies (1950–2026) reporting protein and indispensable amino acid (IAA) composition of freshwater natural food resources, including algae, zooplankton, and zoobenthos. Protein and IAA concentrations were standardized on a dry matter basis and evaluated relative to common carp ( Cyprinus carpio ) amino acid requirement benchmarks. Natural food protein quantity and quality followed the trophic pattern zooplankton > zoobenthos > algae. The IAA profiles in zooplankton and zoobenthos mostly met or exceeded common carp dietary benchmarks, unlike algae which may fall short. Relative trophic position (RTP) was positively associated with all IAAs, supporting the concept of trophic upgrading within freshwater food webs. Lysine exhibited the strongest relationship with RTP ( R 2 = 0.551), demonstrating a high sensitivity to natural food choices by pond carp, whereas methionine showed the weakest relationship, strictly controlled across trophic levels, making it one of the most difficult IAAs to source in pond food web. Our analysis suggests that any ideal protein concept for supplementary feed for ponds should be centered around methionine (as denominator), as most supplementary pond feed protein ingredients may exacerbate the methionine deficiencies and undermine protein utilization. A nutritional ecology framework integrating food web IAA into precision pond feed, with complementary ingredient choices, can greatly enhance the efficiency and cleanliness of pond aquaculture.