Fish are a major component of the coral reef ecosystem, potentially numbering 500 - 1,100 species in Pacific Islands Network (PACN) parks depending on geographic location (Allen et al. 2003, Randall 2005, Randall 2007). This highly diverse assemblage of carnivores, planktivores, herbivores and detritivores serve a variety of ecological functions that affect ecosystem structure, productivity, and sustainability (e.g., Sale 1991, Hixon 1997). Fish assemblages or selected species can also act as indicators of general reef health and provide a warning of environmental stress and potential ecosystem change (e.g., Friedlander and DeMartini 2002). Additionally, fish within the parks are harvested in traditional, subsistence, artisanal, and recreational fisheries (e.g., Craig et al. 2008) which may affect the species composition, abundance and size of targeted species. Fishing is increasingly being recognized as the principal threat to Pacific coral reefs and other marine ecosystems worldwide (e.g., Dayton 1998, Friedlander and DeMartini 2002, Birkeland 2004, Hutchings and Reynolds 2004). In this respect, it is highly probable that most of the Pacific Islands parks can be categorized as "impaired" to "seriously impaired" in terms of their fish communities. Marine Fish ranked 11th in priority as a network Vital Sign. While the harvest of fish is addressed in a separate complementary (fisheries-dependent) protocol, data collected through the Marine Fish Protocol will contribute to the overall understanding by providing an in-water (fisheries-independent) assessment of the size and numerical density of daytime, non-cryptic species within park waters. Monitoring efforts will be conducted concurrently with Water Quality and Benthic Marine Community Vital Signs to maximize data interpretation value.