Characters: Colonies are small and always encrusting. Branches, if formed at all, are small and inconspicuous. Corallites are up to 4 millimetres diameter, with larger corallites near the colony centre, smaller ones at the periphery. They are widely separated. Septa are very long and irregular. They form three distinct cycles in larger corallites. Columellae are sometimes visible deep within the corallite. The coenosteum is blistery.
Colour: Dark green or brown with white corallite rims.
Similar species: No other Galaxea is encrusting. Galaxea acrhelia and G. horrescens have similarly long, sabre-like septa.
Habitat: Vertical rock faces protected from wave action.
