Acropora aculeus is a species of acroporid corals found throughout the Indian Ocean, the central Indo-Pacific, Australia, south-eastern Asia, Japan and the East China Sea. It is also present in the western Pacific Ocean. It is an uncommon species and is particularly prone to coral bleaching, disease, and crown-of-thorns starfish predation; it is also harvested for use in aquaria, and the International Union for Conservation of Nature has assessed it as being a "endangered species". Habitat loss is a large concern.

Description Acropora aculeus forms corymbose, pillow-like structures, the horizontal branches being slender and spreading while the upright branches are narrow and shorter. The corallites are distinctive, longer than they are wide, smooth and polished. This coral is usually yellowish or grey, but can be bright bluish-green, and the tips of the branches are often yellow, pale blue, green or brown. It is usually yellow on the Great Barrier Reef and in the Philippines, but pale brown in western Australia. It is named as ACR ACUL in Coral Codes.

Distribution and habitat Acropora aculeus is native to the Indo-Pacific region, its range extending from the east coast of Africa and Madagascar to Taiwan, Japan, Indonesia, Australia and some island groups in the eastern Pacific Ocean.