Scalpel Coral

About

Found across Indo-Pacific reef slopes from Taiwan down to Australia and east to Samoa, Galaxea horrescens is a branching (arborescent) relative of the more commonly kept Galaxea fascicularis. Its growth form sets it apart from many aquarium corals. Rather than forming a dome or crust, it develops distinct branches tipped with thin-walled, flaring corallites. Each corallite lacks a central columella, and the septa project noticeably above the rim, giving the coral a slightly spiky, open look even when the polyps are withdrawn. Coloration runs toward muted tones: pale brown, soft yellow, and green are typical, sometimes with lighter branch tips. By day the coral tends to look fairly closed up, but after lights out the polyps extend long, tapering translucent tentacles with distinctive white tips. A nice thing to catch during an evening check on the tank. In the wild this species turns up at a wide range of depths on well-lit, well-circulated reef zones, and those preferences translate directly to the aquarium. Moderate flow and moderate lighting suit it well. It falls into intermediate territory care-wise, so some prior reef experience helps, but it is not among the more demanding LPS corals out there.