Malaysia is one of the world's 12 megadiverse countries. Its coral reefs are valuable economic and biological resources, where they are a major attraction for the tourism industry and a natural wave breaker for coastal protection. Coral reefs are the home to a multitude of marine life, and there are 1354 marine fish species in Malaysia, in which 798 are reef-associated. In recent years, coral reefs in Malaysia are under threat, due to uncontrolled development, pollution and overfishing. The Department of Marine Park Malaysia was established to protect and manage the abundant biodiversity in the waters surrounding the 42 islands that make up Malaysia's marine parks covering an area of 2486.13 km2,
To collect the material for this field guide, a total of twelve sites in Perhentian Archipelago and ten sites in Redang Archipelago were investigated by an underwater visual census in 2016-2018, with more than 100 dives. The coverage was limited to shallow reef fishes that are wholly or mainly confined to coral reefs of less than about 30 m depth. In total, 185 reef-associated fish species were recorded from these two archipelagos, belonging to 11 orders and 40 families. Most of the fishes (158 species) belong to the Perciformes. The Pomacentridae predominate (36 species), followed by the Labridae (20 species), Gobidae (14 species), Scaridae (11 species), Apogonidae (11 species), and Serranidae (8 species).