Temperate mesophotic ecosystems (TMEs) consist of complex, three-dimensional habitats created by sessile invertebrates, such as sponges, cnidarians and bryozoans. These benthic animals provide associated mobile fauna with habitats, breeding grounds and refuge from predation. However, structure-forming sponges may also play an important trophodynamic role within TMEs. The sponge loop – a process whereby sponges recycle dissolved organic matter from the water column and make it available to associated benthic detritivores as shed cellular detritus – has helped to explain how oligotrophic environments like coral reefs are able to support diverse and productive fish communities. Here, we aim to unravel food web interactions, focusing on sponge-based pathways in Aotearoa, New Zealand’s, TMEs. Using a combination of visual stomach content analysis and DNA metabarcoding, we have examined the diets of nine TME-associated fish species across a range of trophic positions. The diet analyses indicated the direct consumption of sponge-associated organisms such as brittle stars and suggested there was primary or secondary sponge consumption by some of the fish species examined. This study offers an initial insight into TME food webs and highlights a potential contribution of sponges to fish production in coastal environments, bolstering support for the future protection of TMEs.