Galaxea horrescens

Galaxea horrescens is a reef-associated coral found in the Indo-Pacific region, stretching from Taiwan to Australia and Indonesia to Samoa. This coral species thrives in tropical waters, typically inhabiting depths from the surface down to 40 meters, although most occurrences are found shallower than 20 meters. The colonies of Galaxea horrescens are arborescent, featuring tubular, thin-walled corallites with flared rims and very exsert septa. The tentacles, which are usually extended only at night, are tapering and translucent with distinctive white tips. The coloration of this coral can vary, presenting shades of pale brown, yellow, or green, sometimes with white branch ends. Reproduction in Galaxea horrescens involves the shedding of mature gametes into the coelenteron, which are then spawned through the mouth. The resulting zygote develops into a planktonic planula larva, which undergoes metamorphosis before settling. The life cycle includes early morphogenesis of tentacles, septa, and pharynx. Divers encountering Galaxea horrescens might observe its nocturnal behavior, with tentacles extended under the cover of darkness. This species is currently listed as Least Concern on the IUCN Red List. However, as with many coral species, it is essential to approach with care to avoid damaging these delicate structures.