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Small Polyp Stony Corals

Small polyp stony corals, often abbreviated to SPS corals, are the types of corals most people envision when they hear the word “coral” or read a headline or article about a bleaching event on the Great Barrier Reef or a reef in another tropical part of the world. These colonial animals have been harvesting zooplankton and phytoplankton from the earth’s seas for eons and the success of this model for sustaining life is evident in fossils going back hundreds of millions of years. While very popular and commonly used by reefkeepers and coral researchers alike, the “small polyp stony” appellation is a broad and imprecise generalization of coral species covering hundreds of genera and many thousands of species. As you might guess, the name is derived from the relatively small size of feeding polyps found in SPS species when compared to the much larger and fleshier polyps of large polyp stony, or LPS species.

Until twenty years ago or thereabout, keeping SPS corals in an aquarium for any length of time was thought impossible. Fortunately, some pioneering coralheads decided that this mindset was nonsense and paved the way for the stunning SPS reef displays that are increasingly common today.

Common Small Polyp Stony Species

Although there are thousands of different SPS species found on the world’s reefs, more and more are available to hobbyists through online coral frag sellers and brick-and-mortar retailers all the time. Some of the most common SPS corals available include:

Acropora spp.
Montipora spp.
Pavona spp.
Pocillopora spp.
Porites spp.
Stylophora spp.
Seriatopora spp.
Hydnophora spp.
Cyphastrea spp.
Cynarina spp.
Leptoseris spp.
Psammocora spp.
Platygyra spp.
Turbinaria spp.
Many, many others

Experience Level Required

Generally speaking, SPS corals tend to be more technically tricky to care for and grow for several reasons, including:

They thrive within fairly narrow water quality parameters
These parameters must be stable, with little fluctuation
They require higher lighting levels in select wavelengths
They must have strong shifting, laminar flows that resemble those found on the world’s coral reefs
They have a very thin veneer of living tissue stretched over a calcareous skeleton that the colony builds over time
They are prone to bacterial infections and several difficult-to-detect pests that are mostly invisible until significant, even fatal, damage is done to the colony

We don’t recommend our online SPS coral frags for customers until they have gained experience and had success keeping soft coral and large polyp stony coral species and learned how to maintain the near-pristine water quality that most SPS coral require. It’s just like any other field of expertise; you must first learn the basics before you can move on to more technically challenging aspects.

SPS Coral Lighting Requirements

As mentioned above, SPS corals tend to require intense lighting levels most often found at or near the top of reef displays. This is due to the symbiotic algae living in the tissue of the coral colony. These algae, called zooxanthellae, take light energy and convert it into chemical energy in the form of glucose, amino acids and other essential nutrients for the host coral. Zooxanthellae also provide dissolved oxygen, a byproduct of photosynthesis just like terrestrial pants do. The host coral receives the nutrition that it needs to grow and thrive and the algae receives a home that is more or less safe from the legions of marauding herbivores that live in and on coral reefs and keep algae growth in check.

There are several ways to provide SPS corals with the wavelengths and photoperiods of light they require and different coralheads achieve this different ways. Most of the initial breakthroughs keeping SPS coral frags in captivity occurred using metal halide lamps, which are capable of intense lighting levels that can penetrate to the bottom of most reef displays. Then reefers began experimenting success with T5 fluorescent tube lighting. As LED lighting became more affordable and customizable, LED arrays with controllers gained favor with coralheads all over the world, a trend that continues to this day. If you talk to ten different coralheads, you’ll likely hear at least eight different ways to light your reef display. Indeed, many reefers use a combination of two or more of these types of lighting. They all have attributes and drawbacks and much will depend on your budget, the location of your reef display and your experience level.

Water Flow Requirements

Generally speaking, SPS corals require the kinds of strong shifting, laminar flows found on their native reefs. These currents deliver the volume of planktonic foods that corals also need to thrive and remove the resulting digested waste. The polyps are essentially the mouths of the coral colony, with tentacles that sting, trap and ingest food for the whole colony. If the flows are not strong enough for the colony’s liking, you will achieve little or no polyp extension, the frag and resulting colony will achieve little or no growth and the coloration will likely suffer. Fortunately, getting these kinds of flows with varying levels of intensity and swirling, unpredictable currents in your reef display is pretty easy. These days, all kinds of powerheads and controllers in a wide range of different price points are available to reefers. There aren’t many rules for choosing the right ones for your reef except this: don’t go cheap or you’ll get cheap, unsatisfactory results and gear that won’t last. Reefing is not an inexpensive hobby but like most other endeavors, you get what you pay for.

Feeding SPS Corals

You’ll get the best growth and coloration out of your SPS frags and colonies by providing supplemental feeding on a regular basis. How you go about doing this is mostly up to you. Some reefers use a turkey baster and gently squirt upstream of their SPS corals. Others simply pour in the foods and let the powerheads broadcast it throughout the reef. Some meticulously turn off the powerheads and protein skimmer to help the foods stay distributed throughout the water column, allowing all the corals to catch and ingest the food. You’ll develop your own SPS feeding strategies and techniques over time but make sure to only feed your corals once or twice a week. If you overfeed, you’re adding more nutrients than your system can easily filter out and your water chemistry and your corals will suffer accordingly. Test your water regularly and learn how to interpret your results. It’s a very effective way to monitor and proactively manage the health of your system.

Water Quality Parameters

As we mentioned early on, SPS corals will only thrive in water with optimal water quality parameters that are stable. Achieving stability and learning how to maintain it over time is one of the trickiest aspects of keeping SPS corals but is an essential part of becoming and accomplished and confident reefer. Over time, SPS corals require reef supplements to ensure that they receive amino acids, trace elements and other aspects of coral health but the most basic water chemistry parameters to monitor and provide for your SPS corals include:

Ammonia – 0
Nitrite – 0
Nitrate – As close to 0 as possible.
Calcium – 375-450 parts per million (ppm)
Magnesium – 1300-1350ppm
Carbonate hardness – > 125ppm (Many reefkeepers use alkalinity and carbonate hardness as the same thing but they are different values)
Salinity – 35ppt (parts per thousand) or 1.026 specific gravity
Phosphates – As close to 0 as possible
pH – 8.1-8.3
Temperature – 72-82F

We strongly recommend that you get in the habit of testing your water quality at least once a week and recording the results. This will allow you to notice trends over time, see how your water changes and other system maintenance affect these values and develop an understanding how and why these parameters are co-dependent. This is essential for becoming a more successful coralhead as you take on and achieve success with increasingly challenging SPS coral species.

SPS Coral Frags for Sale Online from CoralFrags.com

If you’re ready to take your reefing to the next level or you’re already successful with SPS corals and can’t resist adding some living eye candy to your cart, you have definitely come to the right place. We’re a small team of professional aquarists who are absolutely crazy about corals of all kinds and love selling SPS frags online to our customers. Each frag we sell is propagated with care in-house and isn’t sold until it is fully healed and has been carefully inspected multiple times to help ensure that you’re getting the coral frag you want without any hitchhiking pests. If we don’t happen to have the SPS coral you’re looking for currently in stock, check back regularly, as it is probably healing in one of our propagation systems and will be listed online shortly. Thanks for looking!

Small Polyp Stony Corals

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