Acropora

Looks how to spot one

Small-polyp stony coral (SPS), branching or plate-shaped

Depending on species it grows as thin or thick branches, bushes or wide flat tables. The surface is dotted with tiny polyps, each around 2 mm, all sharing living tissue and a nerve net over a fast-growing limestone skeleton.1

Personality what they are like

A peaceful reef builder that spends the day soaking up light and may extend its tiny polyps at night to catch plankton. It is regarded as one of the more demanding corals to keep, suited to experienced aquarists.12

Daily activity how busy a day looks

Sessile; it relies on strong, turbulent water movement, like breaking waves on a reef crest, to bring food and keep its surface clean.21

Grooming and care the hands-on bits

An advanced coral. It needs very steady conditions and regular calcium and alkalinity top-ups; reef guidance is roughly 400-450 ppm calcium, 7-12 dKH alkalinity, pH 8.2-8.6, nitrate 0-10 ppm and phosphate close to zero. Newly added colonies are usually inspected for hitchhiking pests.12

Home where they are happiest

A mature, clean reef aquarium with bright lighting, high turbulent flow and stable temperature, generally about 24-27 C (75-80 F), with salinity 1.022-1.025 sg.12

Food basics what goes in the bowl

Gets most of its energy from photosynthetic algae living in its tissue, topped up by plankton caught at night.1

Company who they like around

Each colony is made of many linked polyps; it needs no tankmates but is often grown alongside other small-polyp stony corals.12

The story where it all began

Oken named the genus in 1815, and it has since grown into the largest group of reef-building stony corals. Its branching and table colonies form much of the limestone framework that tropical reefs are built on.1

Recognised by the official bits

Taxonomy (Oken)

Genus named by Oken in 1815, family Acroporidae; more than 149 species described, though hybrids and look-alike species make some uncertain.1