Soft Corals

What are soft corals?

Soft corals are corals that never lay down a rigid stony skeleton. Instead of the calcium carbonate structure that LPS and SPS corals build continuously, they rely on a flexible internal support and microscopic spicules embedded in the tissue, which is why a soft coral colony bends and sways with the current. That single difference drives everything else about keeping them: they place almost no demand on alkalinity and calcium, they tolerate nutrients well, and they are far more forgiving of an immature tank.

The main soft coral groups

Softies cover several distinct groups, each with its own character:

• Zoanthids and palythoa — colonial button polyps in the widest color range of any coral group, spreading across rock in dense mats.
• Mushroom corals — corallimorphs including ricordea, discosoma, rhodactis, and bounce mushrooms. The most tolerant of low light and low flow.
• Leather corals — toadstool, finger, and Kenya tree colonies that grow into substantial centerpiece shapes.
• Xenia and pulsing corals — Xenia, Anthelia, and Cespitularia, which pulse or wave continuously and grow extremely fast.
• Green star polyps — an encrusting purple mat studded with bright waving polyps, the fastest spreader of all.

Soft coral care: light, flow, and nutrients

Most soft corals settle in under low to moderate light and moderate, indirect flow, and almost all of them adapt across a wider range than any stony coral would tolerate. Unusually, many softies prefer a tank carrying some nitrate and phosphate and will decline in ultra-low-nutrient systems run for SPS. Check your reef lighting before placing anything high in the tank, and keep salinity and temperature steady with reliable water testing equipment. Feeding is optional across the whole group.

Managing growth and chemical warfare

The two things that catch soft coral keepers out are speed and chemistry. Green star polyps, xenia, clove polyps, and anthelia can cover a rock in weeks and are very difficult to remove once they reach the main aquascape, so give the fast growers isolated island rocks from the start. Separately, soft corals release compounds into the water to compete for space, which can suppress stony corals in a mixed reef. Run activated carbon, keep up regular water changes, and give softies and SPS separate zones rather than interleaving them.

Starting a soft coral reef

A tank of softies is the most reliable way into the hobby and remains rewarding long after you could keep anything. Start with hardy picks from our beginner corals selection, assemble a coordinated mix with a soft coral pack, or browse the full range of live corals for sale. If you are weighing soft corals against stony ones, our beginner’s guide to soft, LPS, and SPS corals walks through the differences.