Elucidating factors that influence natural resources and diversity can assist managing species and their ecological functions. Key management options include protecting unique locations or implementing restrictions that more broadly protect ecological attributes and their services. To evaluate these 2 options, we examined 23 fish families in 152 unique sites in the Western and Northern Madagascar Ecoregion to test for spatial aggregation, environmental, habitat, and human influences on the fish communities. We found that there were 10 distinct communities of fish and that they were widely distributed in the region. Biomass and diversity were closely associated with the community types and showed weak spatial aggregation and environmental and market influences.