Acropora

Acropora are fast-growing, brightly coloured branching and tabling SPS corals that build wild reefs.

Last reviewed: October 2026

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Overview

Acropora are fast-growing, brightly coloured branching and tabling SPS corals that build wild reefs. They are also the most demanding corals most people keep, unforgiving of any instability, and firmly not a beginner coral. (Acropora species.)

Origin & Habitat

Indo-Pacific reefs, on bright, high-energy reef crests and slopes - the reef-building corals themselves.

Appearance

Branching, tabling, staghorn or bushy stony growth with a distinctive axial tip on each branch, in electric blues, greens, purples and reds with fine polyps.

Placement & Temperament

Fast-growing and needs open space and top billing in the tank. Not chemically aggressive, but it will outgrow and shade slower corals below it.

Tank & Water Conditions

The most demanding common coral - salinity 1.025-1.026, 24-26°C, and rock-steady alkalinity 7.5-9 dKH, calcium 420-450, magnesium 1300-1350, plus very low, controlled nutrients. It needs a mature, months-stable tank and consistent dosing; a single parameter swing can trigger overnight tissue loss (RTN). This is an advanced-keeper coral.

Lighting & Flow

High light (about 200-400 PAR) and strong, turbulent flow.

Feeding

Mainly photosynthetic and fine-plankton feeding; ultra-stable, clean, well-lit water is what really keeps it alive and coloured.

Health & Growth

Beautiful but famously touchy: rapid tissue necrosis (RTN/STN) can strip a colony in hours after a parameter swing. Pests (red bugs, acro-eating flatworms) are common - always dip. Only attempt it in a stable, well-run system.

Pros & Cons

Pros

The pinnacle of reef colour and growth
Fast-growing when thriving
The reward for a mastered tank

Cons

Extremely demanding and unforgiving
Can die overnight from instability
Multiple dedicated pests

Everyday gear for a reef tank

Reef salt mix Mixed fresh for every reef water change. Check price Refractometer Reads salinity, a number worth checking often. Check price Reef light Matched to the light level the care section gives. Check price Reef test kit You cannot manage what you cannot measure. Check price

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Acropora - frequently asked questions

Can a beginner keep acropora?

Honestly, no - not until a tank has been rock-stable for many months and you dose consistently. Acropora is the least forgiving common coral; start with softies, then LPS, then montipora before attempting it.

Why did my acro turn white overnight?

Rapid tissue necrosis (RTN), almost always triggered by a parameter swing (especially alkalinity), a pollutant, or a pest. Acropora demands unwavering stability - which is what makes it the hobby's ultimate test.