Although the coral reefs of Sipadan are not extensive, they exhibit the wide range of species diversity that the Island is famous for. This is the region where Pacific and Indian Ocean biospheres meet.
The diverse population of corals supports hundreds of species of colourful coral dwelling fish and invertebrates and are intermingled with several species of molluscs including giant clams. Octopus can also be found here. Sponges and crinoids are found intermingled with corals or near coral patches and so are several species of marine algae (seaweeds). In or near the habitats created by these one finds a wide variety of interesting creatures including photographers’ favourites such as nudibranchs, lionfish, shrimp, lobsters, anemones, anemone fish, sea horses and a host of others. Diving activity is year round in Sipadan and sea surface temperatures are generally in the range of 25-30°C. Average visibility is in the range of 10-15 metres. Sea temperatures are at their lowest between November and February.