Annual Research & Review in Biology

Seed production of the Indian major carps, catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala), underpins freshwater aquaculture across South Asia, yet survival from hatchling to fry frequently remains low, and larval feeding continues to rely heavily on pond-derived zooplankton and inexpensive oil-cake and bran mixtures. This review critically evaluates how digestive development, live feeds, formulated larval diets and nursery management interact to determine early survival and growth in these species. A critical narrative approach was adopted. Multidisciplinary, biomedical and regional scholarly sources were searched for literature on embryonic and larval development, digestive ontogeny, nutrient requirements, live feeds, weaning and nursery practices, supplemented by backward and forward citation tracking and by targeted checks for corrections and retractions. The evidence shows that Indian major carp larvae begin exogenous feeding with a simple, stomachless digestive tract in which alkaline serine proteases, amylase and lipase are measurable from first feeding and rise over the first month. The larvae ingest progressively larger zooplankton as gape increases, and mixed rotifer and cladoceran diets consistently support better growth than single prey types. Pond zooplankton is protein-rich but variable, and deficient in ascorbic acid, whereas controlled enrichment and phospholipid supplementation improve larval performance. Recent trials with nanoparticulate diets suggest that co-feeding outperforms either live or formulated feed alone, but this evidence is concentrated in very few laboratories and includes one retracted companion study. Nursery trials show that fertilisation, feed ration, water depth and stocking density influence fry yield, although field outcomes remain highly variable. The main unresolved questions concern quantitative nutrient requirements across all three species, the functional maturation of the intestine and pancreas as opposed to enzyme presence, and the transfer of laboratory feeding protocols to commercial nurseries. Progress will depend on standardised developmental time scales, multi-site replicated trials, reporting of survival and economic outcomes, and independent replication of recent formulated-diet findings. Current evidence supports practical improvements in nursery feeding but does not yet justify replacing live food in commercial Indian major carp hatcheries.