Habitat-based metrics are a key component of management plans seeking to sustain diverse and productive fish communities in our marine estates. To be adaptive, these management plans must understand how and why fishes respond to changes in habitat condition over space and time. We used a meta-analysis of 24 independent studies from around the world to explore whether seaweed meadows are important for fish diversity, abundance and replenishment in tropical seascapes. While we found relatively few tropical fish species that could be considered seaweed habitat specialists, seaweed meadows housed a large proportion (61-84% on average) of the local pool of fish species inhabiting seaweed, seagrass and coral reef habitats in each region. Patterns of relative abundance suggest at least 43 fish species may be particularly dependent on tropical seaweed habitat during their life history, including several important fishery target species. While many of these fishes occupied seaweed habitats throughout their life, around half of the species exhibited ontogenetic shifts to/from coral reef. Habitat percent cover was a significant predictor of abundance for many seaweed-associated fishes, indicating their population sizes and recruitment rates are vulnerable to the changes in seaweed habitat condition that arise from local threats and climatic forcing.