How will global fish communities change in response to climate change? Should we expect declines in biomass and abundance or are shifts in community composition with cascading tropic effects more likely? We are currently analysing a large dataset, spanning from the equator to the poles, to model changes in species biomass and abundance under currently predicted climate change scenarios. We are using quantile regression modelling techniques to predict non-linear changes based on three decades of data from the Reef Life Surveys.