The national park situated in the wet zone and receives a 2,000 millimetres (79 in) of annual rainfall.

[2] The rain is received in both southwestern and northeastern monsoon seasons, from April to June and September to November respectively.

Eight species of ornamental fishes also inhabit the reef, along with many vertebrates and invertebrates including crabs, prawns, shrimps, oysters and sea worms.

[2] Chlorurus rhakoura and Pomacentrus proteus are two reef fish species confined to Sri Lanka.

Despite being designated as a protected area, the coral reef has been subject to constant exploitation including removal of breeding ornamental fish for the commercial market.

[5] The two marine national parks of Sri Lanka, Hikkaduwa and Pigeon Island, received little direct impact from the Boxing day tsunami.