<p>Deep-sea anemones from hydrothermal vents remain poorly understood in terms of their trophic strategies and chemosynthetic symbioses. In this study, we investigated the energy acquisition and trophic ecology of actiniarian species from five hydrothermal vent fields along the Central Indian Ridge (CIR), using bulk carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope analyses, amino acid δ¹⁵N (δ¹⁵N_AA), and 16S rRNA amplicon sequencing of symbiotic microbes. The anemones were identified as <i>Alvinactis chessi</i>, <i>Alvinactis</i> sp., and the unclassified Enthemonae. Isotopic data revealed significant spatial variation, indicating differing microbial carbon fixation pathways and trophic interactions. Elevated δ¹³C values of anemones at Mirae-2, Cheoeum, and Kairei suggest a reliance on reductive tricarboxylic acid (rTCA) cycle-based primary production, whereas more ¹³C-depleted δ¹³C values at Onnare and Saero are consistent with the predominance of Calvin–Benson–Bassham (CBB) cycle-based carbon sources. The δ¹⁵N_AA values confirmed varied nitrogen sources, with some anemones likely feeding on <i>Bathymodiolus</i> mussels, shrimps, or polychaetes depending on the availability of these organisms in the community. Notably, despite clear differences in symbiotic microbial community composition between <i>Alvinactis</i> spp. and co-occurring the unclassified Enthemonae, their isotopic signatures were similar, indicating shared dietary sources. These findings demonstrate that while anemones harbor distinct symbiotic microbial&#xa0;communities, their nutritional strategies are primarily shaped by local environmental conditions and prey availability rather than host species identity or symbiont&#xa0;community composition. This highlights the dietary flexibility of deep-sea anemones and underscores the central role of site-specific environmental conditions in structuring trophic interactions at hydrothermal vents.</p>