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𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐢𝐧𝐠 𝐒𝐏𝐒 𝐂𝐨𝐫𝐚𝐥𝐬: 𝐓𝐡𝐞 𝐔𝐥𝐭𝐢𝐦𝐚𝐭𝐞 𝐆𝐮𝐢𝐝𝐞 𝐟𝐨𝐫 𝐑𝐞𝐞𝐟 𝐄𝐧𝐭𝐡𝐮𝐬𝐢𝐚𝐬𝐭𝐬

31 Jan, 2025 735
𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐢𝐧𝐠 𝐒𝐏𝐒 𝐂𝐨𝐫𝐚𝐥𝐬: 𝐓𝐡𝐞 𝐔𝐥𝐭𝐢𝐦𝐚𝐭𝐞 𝐆𝐮𝐢𝐝𝐞 𝐟𝐨𝐫 𝐑𝐞𝐞𝐟 𝐄𝐧𝐭𝐡𝐮𝐬𝐢𝐚𝐬𝐭𝐬

𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐢𝐧𝐠 𝐒𝐏𝐒 𝐂𝐨𝐫𝐚𝐥𝐬:

𝐓𝐡𝐞 𝐔𝐥𝐭𝐢𝐦𝐚𝐭𝐞 𝐆𝐮𝐢𝐝𝐞 𝐟𝐨𝐫 𝐑𝐞𝐞𝐟 𝐄𝐧𝐭𝐡𝐮𝐬𝐢𝐚𝐬𝐭𝐬

 

Introduction

Small Polyp Stony (SPS) corals are the crown jewels of the reef aquarium world, renowned for their vibrant hues, intricate skeletal structures, and demanding care requirements. Unlike their Large Polyp Stony (LPS) counterparts, SPS corals feature small polyps embedded in a rigid calcium carbonate skeleton, requiring pristine water conditions and a dedicated hobbyist.

This guide delves into everything you need to know about SPS coral care, from identifying popular species to maintaining their demanding environments, while addressing common myths and troubleshooting tips along the way.


What Are SPS Corals?

SPS corals are a group of hard corals characterized by their small polyps and rigid skeletal structure. They thrive in nutrient-poor (low nitrate and phosphate) environments, require high light intensity, and demand stable water chemistry. While their care is challenging, the visual payoff of a thriving SPS reef is unparalleled.

SPS corals are ideal for experienced hobbyists who are confident in maintaining consistent parameters and are ready to elevate their reef-keeping game.


Popular SPS Coral Species

Below is a list of the most popular SPS corals, including care requirements and interesting facts to help you choose the right additions for your tank.

1. Acropora (Acropora spp.)

Photo Credit: Ocean Store, Extreme Corals, Top Shelf Aquatics, Vivid Aquariums

Image of Acropora Corals

  • Identification: Vibrant branching coral with fuzzy polyps and intricate skeletal patterns.
  • Lighting (PAR): 250–400.
  • Flow: High, turbulent.
  • Aggression: Moderate; can overshadow other corals.
  • Growth Rate: Fast—new branches may sprout within weeks.
  • Pro Tip: Acropora demands the most stable water conditions, making it a true test of reef-keeping skills.

 

2. Montipora (Montipora spp.)

Photo Credit: Sunnyside Corals, Ocean Store, World Wide Corals, Vivid Aquariums, Ocean Floor   

Montipora Corals  

  • Identification: Smooth or textured surface with a variety of growth forms (encrusting, plating, branching). 
  • Lighting (PAR): 200–350.
  • Flow: Moderate to high.
  • Aggression: Low; tends to grow over other corals if unchecked.
  • Growth Rate: Moderate—up to an inch per month.
  • Pro Tip: Montipora thrives in dynamic lighting and can fluoresce beautifully under actinic lighting.

 

3. Stylophora (Stylophora spp.)

Photo Credit: Top Shelf Aquatics, World Wide Corals, Sunnyside Corals, Tidal Gardens, Live Aquaria, Tidal Gardens, Ocean Store

Image of Stylophora Corals

  • Identification: Compact, bushy branches with tightly packed polyps.
  • Lighting (PAR): 200–350.
  • Flow: Moderate to high.
  • Aggression: Moderate; competes for space aggressively.
  • Growth Rate: Moderate—about 1 inch per month.
  • Pro Tip: Stylophora is more forgiving than Acropora, making it a good entry point for SPS beginners.

 

4. Seriatopora (Seriatopora spp.)

Photo Credit: Extreme Corals, CrazyCoral, The Coral Garden, World Wide Corals, Reeffishcenter Wholesale, Reefs.com

Image of Seriotopora Corals

  • Identification: Thin, delicate branches with a feathery appearance.
  • Lighting (PAR): 200–350.
  • Flow: High.
  • Aggression: Moderate; sensitive to water quality changes.
  • Growth Rate: Moderate.
  • Pro Tip: This coral is a great indicator species—if it thrives, your tank conditions are excellent.

 

5. Pocillopora (Pocillopora spp.)

Photo Credit: Tidal Gardens, World Wide Corals, RecifAtHome, Live Aquaria, Extreme Corals, Vivid Aquariums, World Wide Corals

Image of Pocillopora Corals

  • Identification: Rounded, bushy colonies with small, bumpy polyps. Available in pastel shades like pink, green, and cream.
  • Lighting (PAR): 200–350.
  • Flow: Moderate to high.
  • Aggression: Moderate; can release a mucus-like substance to deter neighboring corals.
  • Growth Rate: Moderate—up to 1 inch per month.
  • Pro Tip: Pocillopora is resilient and beginner-friendly among SPS corals. However, its "polyp bailout" ability allows it to spread to unintended areas, so keep an eye on where new colonies might pop up.

 

6. Hydnophora (Hydnophora spp.)

Photo Credit: The Biota Grouo, Tidal Gardens, Reef Builders, Jason Fox, Top Shelf Aquatics

Image of Hydnophora

  • Identification: Known as Horn Coral, it features thick branches and vibrant colors like green or yellow. Polyps are large and prominent, often extending to capture prey.
  • Lighting (PAR): 200–350.
  • Flow: High.
  • Aggression: High; sends out long sweeper tentacles that deliver potent stings to nearby corals.
  • Growth Rate: Fast—up to 2 inches per month.
  • Pro Tip: Keep Hydnophora isolated; its aggressive nature makes it a "tank bully" if placed too close to other corals.

 

7. Porites (Porites spp.)

Photo Credit: Tidal Gardens, Vivid Aquariums, Tidal Gardens, Vivid Aquariums, World Wide Corals, The Coral Farm

Image of Porites Corals

  • Identification: Smooth-surfaced SPS coral with tiny, embedded polyps. Can grow in encrusting, plating, or branching forms.
  • Lighting (PAR): 200–350.
  • Flow: Moderate to high.
  • Aggression: Low; rarely competes for space aggressively.
  • Growth Rate: Slow—less than 1 inch per month.
  • Pro Tip: Porites are hardy and often found in wild reef-building systems. They’re a great choice for tanks mimicking natural coral reef environments.
  • Fun Fact: The is the type of coral that has Christmas Tree Worms!

 

8. Pavona (Pavona spp.)

Photo Credit: Algae Barn, Reef Builders, Tidal Gardens, World Wide Corals, Live Aquaria, Reef Builders

Images of Pavona Corals

  • Identification: Also known as Cactus Coral, Pavona has an encrusting or plating growth pattern with small, clearly defined polyps.
  • Lighting (PAR): 200–350.
  • Flow: Moderate to high.
  • Aggression: Moderate; can overgrow nearby corals if left unchecked.
  • Growth Rate: Moderate—up to 1 inch per month.
  • Pro Tip: Pavona can quickly encrust rockwork, making it an excellent coral for filling gaps in your aquascape.

 

9. Turbinaria (Turbinaria spp.)

This is not "technically" an SPS. It is usually grouped with SPS but its polyps a quite large and is usually considered an MPS (Middle Polyp Stony). But since we never hear about MPS corals I thought it made the most sense to add it to this article.

Photo Credit: World Wide Corals, Algae Barn, Reef Builders, World Wide Corals

Image of Turbinaria

  • Identification: Known as Pagoda or Cup Coral, Turbinaria features a unique scroll or cup-like structure with small polyps visible during the day.
  • Lighting (PAR): 200–350.
  • Flow: Moderate to high.
  • Aggression: Low; generally non-aggressive.
  • Growth Rate: Slow—less than 1 inch per month.
  • Pro Tip: Turbinaria is more tolerant of lower light levels than many SPS corals, making it a good choice for tanks with variable lighting zones.

 

10. Leptoseris (Leptoseris spp.)

Photo Credit: Vivid Aquariums, Tidal Gardens, Whitlyn Aquatics, Vivid Aquariums, Tidal Gardens, World Wide Corals

Image of Leptoseris Corals

  • Identification: Features a distinctive encrusting or plating growth form with small, closely packed polyps. Comes in earthy tones like orange, yellow, or green.
  • Lighting (PAR): 100–200.
  • Flow: Moderate.
  • Aggression: Low; rarely competes for space.
  • Growth Rate: Moderate—up to 1 inch per month.
  • Pro Tip: Leptoseris is one of the few SPS corals that thrives in lower light conditions, making it perfect for shaded or lower PAR areas in your tank.

 

11. Cyphastrea (Cyphastrea spp.)

Photo Credit: Top Shelf Aquatics, Tidal Gardens, World Wide Corals, Tidal Gardens, Sunnyside Corals, World Wide Corals

Image of Cyphastrea Corals

  • Identification: Encrusting coral with a bumpy surface and small, brightly colored polyps. Often features contrasting polyp and tissue colors for added visual interest.
  • Lighting (PAR): 100–200.
  • Flow: Moderate to low.
  • Aggression: Low; does not grow aggressively or overshadow other corals.
  • Growth Rate: Moderate.
  • Pro Tip: Cyphastrea is one of the most versatile SPS corals, thriving even in shaded or low-light areas of the tank. It’s a fantastic coral for filling in tricky spaces.

General Care Tips for SPS Corals

1. Lighting

  • High-intensity lighting is non-negotiable. Use LED, T5, or metal halide systems to achieve PAR levels of 200–400, depending on the coral.
  • Gradually acclimate corals to intense lighting to prevent bleaching.

 

2. Water Quality

Maintain stable parameters:

  • Temperature: 75–78°F (24–26°C) – Stable temperatures are crucial; fluctuations can stress SPS corals.
  • Salinity: 1.025–1.026 specific gravity – Precision is key; sudden salinity swings can cause tissue loss.
  • Calcium: 420–450 ppm – SPS corals depend on calcium for building their rigid skeletons.
  • Alkalinity: 7.5–9 dKH – Stability is more important than hitting a specific number; avoid rapid shifts.
  • Magnesium: 1300–1400 ppm – Helps maintain calcium and alkalinity balance; prevents precipitation issues.
  • Nitrates: 1–5 ppm – A completely nutrient-starved system can lead to pale, unhealthy corals.
  • Phosphates: 0.01–0.03 ppm – Essential for metabolism but should be kept at ultra-low levels to prevent algae outbreaks.
  • pH: 8.1–8.4 – A stable pH helps coral skeletons grow efficiently

 

3. Water Flow

  • High, alternating flow is essential to prevent detritus buildup and deliver nutrients. Use wave makers or gyres for a natural flow pattern.

 

4. Feeding

  • While photosynthesis is their primary energy source, SPS corals benefit from supplemental feeding:
    • Foods: Phytoplankton, marine snow, and amino acids.
    • Feed sparingly to avoid water quality issues.

Troubleshooting Common Problems

1. Coral Bleaching

  • Symptoms: Loss of color due to expelled zooxanthellae.
  • Causes: Excessive light, unstable parameters, or high temperatures.
  • Solution: Reduce light intensity, stabilize water chemistry, and ensure adequate flow.

 

2. Tissue Recession

  • Symptoms: Exposed skeleton at the base or tips of branches.
  • Causes: Nutrient imbalances or aggressive neighboring corals.
  • Solution: Adjust water parameters and move coral away from aggressive species.

 

3. Poor Polyp Extension

  • Symptoms: Polyps remain retracted.
  • Causes: Low flow, pests, or poor water quality.
  • Solution: Increase flow and check for pests like flatworms or red bugs.

Myths About SPS Corals

1. "SPS corals only grow in nutrient-free tanks."

Reality: While SPS corals prefer low nutrients, they do not thrive in a completely sterile tank. Nitrates (1–5 ppm) and phosphates (0.01–0.03 ppm) are essential for healthy growth and coloration. Running a system with undetectable nutrients can lead to coral starvation, faded colors, and slow tissue recession. Balanced nutrient export (via skimmers, refugiums, and media) is key—too much and you get algae, too little and your SPS will starve.

 

2. "All SPS corals are impossible for beginners."

Reality: Some SPS species are demanding (looking at you, Acropora), but others like Montipora, Bird’s Nest, and Pocillopora are much more forgiving. These corals tolerate minor fluctuations and are great for hobbyists transitioning from LPS or soft corals to SPS. Beginners should start with these before attempting ultra-sensitive species like Acropora.

 

3. "SPS corals grow slowly."

Reality: Growth rate varies significantly between species. Acropora and Montipora can grow inches per month under ideal conditions, whereas corals like Stylophora or Porites are slower. If your SPS isn’t growing, check your alkalinity, calcium, and magnesium levels—these are the building blocks of coral skeletons.

 

4. "You must dose daily to keep SPS corals alive."

Reality: While dosing alkalinity, calcium, and magnesium is often necessary for SPS tanks, the frequency depends on the coral load and tank size. Some tanks require daily dosing, others can go days or weeks without adjustments, especially if frequent water changes are performed.

 

5. "You can’t keep SPS in a mixed reef tank."

Reality: SPS corals can thrive in mixed reefs, but placement is important. They should be positioned in higher light and high-flow areas, while LPS and soft corals occupy lower-energy zones. Be cautious of allelopathy (chemical warfare) between corals—some LPS corals like Torches, Hammers, and Chalices have long sweeper tentacles that can sting and damage SPS.


FAQs About SPS Corals

Q: Can SPS corals survive in low light?

A: No. SPS corals require high-intensity lighting (200–400 PAR depending on species) to support photosynthesis. Low light can lead to brown, unhealthy corals or slow tissue loss.

 

Q: How can I tell if my SPS coral is happy?

A: Signs of a thriving SPS coral include:

1. Vibrant, well-defined coloration
2. Consistently extended polyps
3. Steady, visible growth over weeks/months
4. No signs of tissue recession or bleaching

 

Q: What’s the biggest mistake new SPS keepers make?

A: Inconsistent water parameters! Fluctuating alkalinity, calcium, and magnesium levels stress SPS corals. Test regularly and maintain stability to prevent STN (slow tissue necrosis) or RTN (rapid tissue necrosis).

 

Q: Do SPS corals need to be fed?

A: Yes, while SPS corals primarily rely on photosynthesis, they can benefit from supplemental amino acids, phytoplankton, and coral foods like Reef Roids. Feeding helps improve coloration and polyp extension.


Conclusion

SPS corals are the pinnacle of reef-keeping for advanced aquarists. Their stunning colors, intricate growth patterns, and rewarding challenges make them a favorite among experienced hobbyists. With stable water chemistry, high-quality lighting, and diligent care, you can create a thriving SPS reef that is as captivating as it is rewarding.

Happy Reefing!