SPS coral

SPS coral is short for small polyp stony coral: a hard coral with tiny polyps and a skeleton made of calcium carbonate. SPS corals include some of the most striking aquarium animals, and also some of the most demanding. This guide explains what they are, what separates them from soft and LPS corals, and what they need in a home reef tank.

What SPS coral is

Corals are animals that live in colonies. Stony corals build a rigid skeleton. Within that group, the shorthand splits by polyp size. SPS corals have small polyps packed across the surface of the colony. Many SPS species grow as branching, table or plating shapes, which is why they create the structure that gives a reef tank its silhouette.

Most SPS corals also host microscopic algae called zooxanthellae inside their tissue. The coral gives the algae shelter, and the algae provide energy through photosynthesis. That partnership is why lighting matters so much: the coral is partly fed by light.

SPS versus LPS versus soft corals

• SPS. Small polyps, often fine branches or plates, usually the most sensitive to unstable water and the most light-hungry. Examples include staghorn, acropora and montipora types.
• LPS. Large, fleshy polyps and separate, often rounded colonies, such as brain, hammer and torch corals. Generally more forgiving than SPS. See the LPS coral guide.
• Soft corals. Flexible bodies without a rigid skeleton, such as leathers, mushrooms and zoanthids. Often the easiest corals for a new tank.

What SPS corals need

A tank that suits SPS is a tank that has already settled down. These are the conditions to aim for before you buy:

• Stable water chemistry. SPS corals react to swings that hardier corals ignore. Consistent salinity, temperature, and mineral levels matter more than any single reading.
• Strong, consistent lighting. Enough intensity and the right spectrum for the algae inside the coral. Consistency matters as much as strength.
• Strong, random flow. SPS colonies grow best with brisk, varied water movement, which also keeps waste and sediment from settling on them.
• Calcium and carbonate. Skeleton growth uses these, so reef keepers test for them and replace what the tank consumes.
• Low and stable nutrients. The tank must be mature enough to process waste without letting it accumulate.

Buying SPS coral

SPS coral is usually sold as frags, small pieces grown onto a plug or rock that will grow into a colony. Captive-grown frags are common and tend to adapt to aquarium conditions more readily than wild-collected colonies. Good questions to ask a seller:

• Has this frag been in your system long enough to be settled?
• What lighting and flow is it currently under?
• Is it grown from a captive colony?

A store that keeps its SPS under strong lighting and can answer those questions is a store that understands the animals it sells. It is also worth checking a frag for pests before adding it to your tank, and dipping according to the seller's guidance.

Finding SPS corals in Canada

• Aquarium stores in Ontario
• Aquarium stores in Alberta
• Aquarium stores in British Columbia
• Search the whole Canadian directory

Keep reading

• Saltwater aquarium for beginners — New to saltwater? Learn what a marine tank needs, how to cycle it, and the equipment to start with — then find an aquarium store near you in Canada.
• LPS coral — LPS coral explained: what large-polyp stony corals are, popular examples, and how to keep them healthy in a home reef aquarium.
• Beginner corals — The hardiest corals for a first reef tank, what makes a coral beginner-friendly, and how to find coral sellers near you in Canada.
• Reef tank setup — How to set up a reef tank step by step: tank, rock, sand, water, cycling, lighting and flow — plus where to find reef stores in Canada.
• Coral care — Coral care basics: light, flow, water parameters, feeding and placement, so the corals you buy from a local store settle in and grow.

General information only. Confirm livestock availability and care needs with a local reef store.