LPS, SPS or Soft Corals: A Guide to Choosing Your First Corals

When starting a reef aquarium, choosing the first corals can seem complicated. Soft corals, LPS and SPS corals are three broad categories commonly used in the aquarium hobby to distinguish corals with different structures and requirements.

Some are relatively tolerant and make good choices for a first reef aquarium, while others require greater parameter stability, suitable lighting or stronger water flow.

What are the differences between soft corals, LPS and SPS corals? Which corals are suitable for beginners? Before selecting the first specimens, it is essential to understand their main requirements in order to choose corals suited to the aquarium and the aquarist's level of experience.

What Is the Difference Between Soft Corals, LPS and SPS Corals?

The terms soft corals, LPS and SPS corals are widely used in the reef aquarium hobby. They provide a simple way to distinguish different types of corals according to their structure and, in the case of stony corals, the size of their polyps.

Soft corals do not have the rigid calcium carbonate skeleton characteristic of stony corals. Some, such as Sarcophyton and Sinularia, nevertheless contain small internal calcareous structures known as sclerites, which help support their tissues.

LPS corals, or Large Polyp Stony corals, are stony corals with a calcium carbonate skeleton and generally large, fleshy polyps. Euphyllia, Catalaphyllia and Trachyphyllia are among the best-known examples in reef aquariums.

SPS corals, or Small Polyp Stony corals, are also stony corals, but they have small polyps and often form branching, encrusting or massive calcareous colonies. Acropora, Montipora and Seriatopora are among the best-known genera.

These categories are useful for aquarists, but they do not constitute a complete scientific classification. Requirements can also vary considerably between species within the same group.

Are Soft Corals Suitable for Beginners?

Soft corals are often recommended for those starting out in reefkeeping. Many tolerate certain environmental variations better than more demanding stony corals.

They do not build a massive calcium carbonate skeleton like LPS and SPS corals. Their care therefore does not involve the same calcium and alkalinity consumption associated with calcification.

Sarcophyton and Sinularia

The genera Sarcophyton and Sinularia include some of the best-known soft corals in the aquarium hobby.

Sarcophyton, commonly known as leather corals, generally have a thick stalk topped by an upper section covered with numerous small polyps. Some species can grow relatively large and therefore need sufficient space for their growth.

Sinularia can develop a variety of forms, including branching shapes. As with other corals, their exact lighting and water flow requirements depend on the species and the conditions in which they were previously kept.

Discosoma and Ricordea

Discosoma and Ricordea are corallimorphs. They are often grouped with soft corals in aquarium terminology, even though they belong to a different zoological group.

They are appreciated for their fleshy tissues and sometimes very intense colors. Some species can multiply readily under suitable conditions.

They can be an interesting option for a reef aquarium when their specific lighting, water flow and placement requirements are met.

What About Zoanthus?

Zoanthus are also frequently grouped with soft corals in the aquarium hobby. They form colonies made up of numerous polyps and can gradually spread across rock surfaces.

From a scientific perspective, however, Zoanthus belong to the Zoantharia and are not octocoral soft corals like Sarcophyton or Sinularia.

This distinction does not prevent them from being widely kept in reef aquariums, where they are particularly valued for their wide variety of colors.

What Is an LPS Coral?

LPS corals (Large Polyp Stony) are stony corals with a skeleton composed primarily of calcium carbonate and generally large, fleshy polyps.

Popular LPS corals in reef aquariums include Euphyllia, Catalaphyllia and Trachyphyllia.

A significant proportion of their energy requirements is met through photosynthesis carried out by their symbiotic algae. Many LPS corals can also capture food particles and zooplankton using their tentacles.

The growth of their skeleton consumes calcium and alkalinity (KH). Maintaining stable parameters therefore becomes increasingly important as the number of stony corals and their growth increase in the aquarium.

Some LPS corals can be an interesting next step after the first soft corals, provided suitable species are selected and sufficiently stable parameters are maintained.

What Is an SPS Coral?

SPS corals (Small Polyp Stony) are stony corals characterized by small polyps and a calcium carbonate skeleton.

Acropora, Montipora and Seriatopora are among the best-known genera in reef aquariums. Depending on the species, their colonies may develop branching, plating, massive or encrusting growth forms.

SPS corals are particularly valued for their shapes and colors, but many species have more demanding care requirements.

They generally require highly stable water parameters, particularly alkalinity and calcium. Magnesium also plays an important role in the chemical balance that supports calcification.

Many SPS corals also prefer relatively intense lighting and strong, irregular water flow. These requirements nevertheless vary between species: the term SPS does not mean that all these corals should be placed under exactly the same light intensity or exposed to the same flow.

For a first reef aquarium, gaining experience with more tolerant corals before moving on to the most demanding SPS corals is therefore generally preferable.

What Lighting Is Best for Beginner Corals?

Light plays an essential role for many reef corals that host photosynthetic symbiotic algae. However, there is no single ideal light intensity for all corals.

Some soft corals grow well under moderate lighting, while many SPS corals require more intense light. LPS coral requirements often fall somewhere in between, although the appropriate level primarily depends on the species.

Coral placement within the aquarium is therefore important. Water depth, lighting intensity, aquascape and shaded areas directly influence the amount of light a coral receives.

A newly introduced coral should also not be exposed suddenly to a much higher light intensity than it was previously accustomed to. Gradually adjusting its placement or the lighting intensity can help reduce stress.

What Water Flow Do Soft, LPS and SPS Corals Need?

Water flow circulates water around corals and supports exchanges with their surrounding environment.

Requirements again vary between species. Many soft corals prefer moderate flow that allows their polyps to extend properly.

LPS corals with particularly fleshy tissues should be positioned carefully: excessively strong, direct flow can prevent proper expansion or damage their tissues.

Many SPS corals, by contrast, prefer stronger water movement. Variable, multidirectional flow allows water to circulate around the different parts of the colony.

Water flow should therefore be adapted to the corals present rather than applying the same rule throughout the entire aquarium.

What Water Parameters Should Be Monitored for Corals?

Regardless of the type of coral selected, reef aquarium stability remains essential.

Temperature, salinity and pH should remain within suitable ranges for a reef aquarium, while sudden fluctuations should be avoided. Nitrate and phosphate levels should also be monitored. Their presence does not necessarily indicate a problem, but unsuitable concentrations or significant fluctuations can disrupt the aquarium's balance.

With LPS and SPS corals, monitoring alkalinity (KH), calcium and magnesium becomes increasingly important. These corals use calcium and carbonates, among other elements, to build their skeletons.

As the number and growth of stony corals increase, their consumption can become more significant. Water changes may be sufficient in some lightly stocked reef aquariums, while an aquarium containing many growing corals may require more regular monitoring and supplementation.

What Are the Best Corals for Beginners?

When choosing the first corals for a reef aquarium, it is best to select species whose requirements genuinely match the maturity of the aquarium, the available lighting and the ability to maintain stable water parameters.

Some soft corals often make a good starting point because of their relatively high tolerance to environmental variations. Corallimorphs such as Discosoma or Ricordea can also be considered depending on the conditions in the aquarium.

Once the aquarium is stable and its operation is better understood, some LPS corals can provide a gradual introduction to the requirements of calcifying corals.

The most demanding SPS corals are generally better suited to an established and well-managed reef aquarium where lighting, water flow and, above all, water parameters remain sufficiently stable.

There is therefore no single “best coral” for beginners. The right choice depends primarily on the aquarium and its stability. Understanding the differences between soft corals, LPS and SPS corals makes it possible to select suitable species and gradually develop a diverse reef aquarium.