Acropora horrida

Acropora horrida is an open, irregular staghorn, its branches spreading loosely rather than forming a tight thicket. In aquaculture it appears in blue, purple and green, often with different tones on different parts of the same colony. Growth is moderate, and the open structure means a settled colony can size up impressively without becoming overly dense.

Care

An advanced Acropora that belongs in a mature, stable SPS system. Alkalinity stability is the single most important factor — hold it steady, and keep calcium and magnesium consistent alongside it. It wants high light, roughly PAR 250–400, introduced gradually to new frags, and strong random flow from shifting directions; a constant jet will damage tissue and distort growth. The open branching helps flow reach the interior, but detritus should still not be allowed to settle. An encrusting base and lively polyp extension are the reliable health signs, while paling or recession after a parameter change is a warning to return to stability rather than chase corrections.

Placement and growth

Place it at the top of the aquascape with at least 2 in of clearance from neighbours, plus extra room for its loose, spreading branches. It is peaceful, but fast lateral growth can shade corals below, so think about what sits underneath it. Secure the mount well, let it encrust, and prune thoughtfully only once the colony is fully established.