Sustaining live corals in a reef tank takes more than adding saltwater, rock, light, and a few colorful frags. Live corals are sensitive marine animals that depend on stable water quality, proper lighting, good water flow, balanced nutrients, smart placement, careful coral selection, and consistent observation. When those pieces work together, corals can open fully, hold strong color, grow new tissue and skeleton, and become the living foundation of a beautiful reef aquarium.

Here at Extreme Corals, we have worked with live corals for decades. We have selected, photographed, shipped, and sold hundreds of thousands of corals, and in our experience, the reef keepers who succeed long term are the ones who build stability first. A coral may look stunning when it arrives, but its long-term health depends on the environment it enters. Lighting, flow, salinity, alkalinity, calcium, magnesium, nitrate, phosphate, pest prevention, and placement all matter.

This complete guide explains the essential care tips for sustaining live corals in reef tanks, including water quality, coral lighting, water flow, nutrient management, coral identification, coral feeding, disease prevention, common problems, and how to choose corals that match your aquarium. If you are building or improving a reef tank, start with our coral care guide, review our live coral care guide, and browse our new arrival corals.

Why Live Corals Need Stable Reef Tank Conditions

Live corals come from reef environments where water movement, light, mineral balance, and biological stability are naturally connected. In a home reef tank, the aquarium keeper has to recreate enough of that stability for corals to survive and grow. Corals can adapt to a range of conditions, but they do not respond well to constant swings.

Stable reef tank conditions help support:

• Coral tissue expansion
• Polyp extension
• Healthy coloration
• Stony coral skeleton growth
• Feeding response
• Recovery after shipping or fragging
• Resistance to pests, algae irritation, and disease
• Long-term coral survival

In our experience, many coral problems are not caused by one obvious mistake. They often come from several smaller issues happening together, such as unstable salinity, weak flow, excessive nutrients, poor placement, or lighting that changed too quickly.

Understanding the Main Types of Live Corals

Before you can care for live corals properly, you need to understand what type of coral you are keeping. Different corals have different light, flow, nutrient, feeding, and spacing needs. A soft coral, a Hammer Coral, a mushroom coral, and an Acropora should not all be treated the same way.

Soft Corals

Soft corals do not build large hard skeletons like stony corals. Many are more forgiving and can be good choices for newer reef keepers. They often add movement, texture, and color to the aquarium. Examples include leather corals, Clove Polyps, mushrooms, Green Star Polyps, Zoanthids, and Kenya Tree corals. Browse our soft corals for sale.

LPS Corals

LPS corals, or large polyp stony corals, have hard skeletons and larger fleshy polyps. Many LPS corals are prized for movement, color, and feeding response. Examples include Torch Corals, Hammer Corals, Frogspawn Corals, Favia, Favites, chalices, Acanthophyllia, Trachyphyllia, and Scolymia. Browse our LPS corals for sale.

SPS Corals

SPS corals, or small polyp stony corals, usually need stronger lighting, stronger random flow, and very stable alkalinity. Examples include Acropora, Montipora, Birdsnest-style corals, Stylophora, and Pocillopora. Browse our SPS corals for sale.

Water Quality for Sustaining Live Corals

Water quality is the foundation of coral care. Corals live directly in the water, so changes in salinity, temperature, alkalinity, nutrients, and minerals affect them quickly. A reef tank with unstable water may keep corals alive for a while, but long-term growth and color usually suffer.

These ranges are starting guidelines. The exact best range can vary by system, but stability is always important. For a deeper breakdown, read our reef tank water parameters guide.

Testing Reef Tank Water Regularly

Water testing helps reef keepers make decisions based on real information instead of guessing. A coral may look closed or pale for several reasons, and test results can help narrow down the cause. Testing is especially important before adding new corals, after equipment problems, before larger water changes, and when corals begin acting differently.

Important tests for coral tanks include:

• Salinity
• Temperature
• pH
• Alkalinity
• Calcium
• Magnesium
• Nitrate
• Phosphate
• Ammonia and nitrite in new or troubled systems

In our experience, alkalinity and salinity are two of the most important numbers to keep stable. A tank can have expensive equipment and beautiful corals, but if salinity and alkalinity swing constantly, coral health usually declines. Read our reef tank water testing guide for a complete testing schedule.

Salinity Stability for Live Corals

Salinity is one of the most important reef tank parameters because corals and invertebrates are sensitive to salt concentration changes. Evaporation removes freshwater but leaves salt behind, so salinity rises as water evaporates. This is why reef tanks should be topped off with fresh RO/DI water, not saltwater.

Good salinity habits include:

• Use a calibrated refractometer or reliable digital salinity meter.
• Top off evaporation with RO/DI freshwater.
• Use mixed saltwater only for water changes.
• Match new saltwater to the display tank before water changes.
• Check salinity after auto top-off problems or large maintenance work.

Stable salinity protects coral tissue and helps prevent avoidable stress.

Alkalinity, Calcium and Magnesium

Alkalinity, calcium, and magnesium are especially important for LPS and SPS corals because stony corals use calcium carbonate to build skeleton. If these values are unstable, corals may grow slowly, lose tissue, or become more sensitive to light, flow, and nutrient changes.

Alkalinity often changes faster than calcium or magnesium, so it should be tested more often in stony coral tanks. Stable alkalinity usually matters more than chasing a perfect number. A reef tank sitting steadily at 8.3 dKH is often better than a tank swinging from 7 to 10 dKH.

Stony coral systems may need:

• Regular alkalinity testing
• Calcium and magnesium monitoring
• Consistent water changes
• Two-part dosing, kalkwasser, or a calcium reactor when coral demand increases
• Slow corrections instead of sudden chemical adjustments

Soft coral tanks may use these minerals more slowly, but they still benefit from stable reef chemistry.

Lighting Requirements for Live Corals

Lighting is essential because many corals are photosynthetic. They host symbiotic algae called zooxanthellae that use light to help produce energy for the coral. However, not every coral wants the same amount of light. Too much light can bleach or shrink corals. Too little light can cause poor color, slow growth, or weak extension.

General lighting needs often look like this:

• Mushrooms and many soft corals: low to moderate light
• Zoanthids: low to moderate light, depending on variety
• Many LPS corals: moderate light
• Torch, Hammer and Frogspawn Corals: moderate light with gradual acclimation
• Many SPS corals: moderate to high light with strong stability

Do not place every coral at the same height under the same intensity. Coral placement should match the coral’s lighting needs. For more detail, read our best reef tank lighting guide.

Light Acclimation for New Corals

New corals should be light acclimated because they may come from different lighting than your tank. Even if your light is excellent, the coral can be shocked if it is placed too high or under too much intensity immediately after shipping.

Good light acclimation practices include:

• Start new corals lower in the tank when appropriate.
• Use your fixture’s acclimation mode if available.
• Reduce intensity temporarily for sensitive new corals.
• Move corals upward slowly only after they look stable.
• Watch for bleaching, fading, shrinking, or poor extension.

In our experience, many coral losses happen because reef keepers try to force color and growth too quickly. Slow acclimation is safer than sudden light shock.

Water Flow for Live Corals

Water flow helps deliver oxygen, nutrients, and trace elements while removing waste and preventing detritus from settling on coral tissue. Flow also affects how corals expand, feed, clean themselves, and manage the byproducts of photosynthesis.

Different corals need different flow:

• SPS corals: stronger random flow
• LPS corals: moderate indirect flow
• Soft corals: low to moderate flow depending on species
• Mushrooms: lower to moderate flow
• Zoanthids: enough flow to keep debris away without blasting polyps

Flow should move water around the coral, not rip tissue off the skeleton. Fleshy LPS corals like Torch, Hammer, Frogspawn, Acanthophyllia, Trachyphyllia, and Scolymia can be damaged by direct powerhead flow. Read our water flow and coral health guide for more help.

Nutrient Management for Live Corals

Nutrients are often misunderstood in reef keeping. High nitrate and phosphate can fuel algae and stress certain corals, but zero nitrate and zero phosphate can also cause problems. Corals need nutrients. Many reef tanks look best when nutrients are measurable, controlled, and stable.

Balanced nutrients help support:

• Coral tissue fullness
• Zooxanthellae function
• Color stability
• Feeding response
• Soft coral and LPS health
• Biological stability

Excess nutrients can create algae pressure and brown out some corals. Nutrients that are too low can cause pale color, thin tissue, poor LPS expansion, and higher sensitivity to light. The goal is balance, not zero. Read our nitrates in reef tanks guide for more detail.

Filtration and Protein Skimming

Good filtration supports live corals by removing waste, improving water clarity, and helping stabilize nutrients. A reef tank does not need to be sterile, but it does need reliable export. Fish feeding, coral mucus, uneaten food, detritus, and dissolved organics all build up over time.

Useful filtration tools may include:

• Protein skimmers
• Mechanical filter socks, cups, or floss
• Activated carbon when appropriate
• Live rock and biological filtration
• Refugiums or macroalgae systems
• Regular water changes

The right filtration depends on the tank. A heavily stocked fish and coral system needs more export than a lightly stocked soft coral tank. The goal is to keep water clean enough for coral health without stripping nutrients so low that corals starve.

Coral Identification and Selection

One of the best ways to keep live corals alive is to choose the right coral before you buy it. Different coral types have different care requirements, and not every coral is right for every tank. A new reef keeper should not start with the most demanding SPS coral or a delicate collector LPS before the tank is stable.

Before buying a coral, ask:

• Is my tank mature enough for this coral?
• Does my lighting match its needs?
• Does my flow match its needs?
• Do I have room for growth and aggression?
• Can it sting nearby corals?
• Does it spread quickly?
• Is the coral healthy in the photo?
• Do I understand how to acclimate and place it?

Healthy coral selection matters. Look for good tissue coverage, stable color, normal extension for the coral type, and no obvious melting, brown jelly, or fresh recession. Browse our Scott's Handpicked Corals for standout pieces selected for color and quality.

Coral Placement in Reef Tanks

Coral placement determines whether a coral receives the right light, flow, and spacing. A coral can be healthy when it arrives and still fail if it is placed in the wrong zone. Placement also affects future growth, coral aggression, shading, and how easy the tank is to maintain.

Good coral placement considers:

• Lighting needs
• Water flow needs
• Coral aggression
• Future growth size
• Distance from neighboring corals
• Whether the coral spreads across rock
• Sandbed irritation
• Whether fish or invertebrates may disturb it

Fast-growing corals such as Clove Polyps, Green Star Polyps, some mushrooms, and some Zoanthids should be placed with growth control in mind. Fleshy LPS corals should have enough space to expand without rubbing rock or being blasted by flow. Read our coral placement guide before adding new pieces.

Coral Feeding and Supplementation

Many corals are photosynthetic, but feeding can still help. Some corals receive much of their energy from light, while others benefit from captured food, dissolved nutrients, fish waste, and fine suspended foods. Feeding should support coral health without polluting the tank.

Coral feeding options may include:

• Small meaty foods for many LPS corals
• Fine particle coral foods for SPS and filter-feeding corals
• Zooplankton-style foods
• Phytoplankton-style foods when appropriate
• Fish-fed nutrient systems
• Occasional target feeding for corals that accept food

Supplements may be needed when coral demand grows. Stony coral tanks may require alkalinity, calcium, and magnesium supplementation beyond water changes. However, supplements should be based on testing, not guessing. Never add products blindly because a coral looks stressed.

Disease Management and Prevention for Live Corals

Coral disease and tissue loss can move quickly, especially in fleshy LPS corals and stressed SPS corals. Prevention is always better than emergency treatment. Healthy water, stable chemistry, pest prevention, good flow, and careful handling reduce many disease risks.

Coral disease prevention includes:

• Inspecting new corals before they enter the display
• Using coral dips when appropriate
• Quarantining new corals when possible
• Avoiding tissue damage during handling
• Keeping alkalinity and salinity stable
• Removing dying tissue or problem frags when necessary
• Watching closely for brown jelly, recession, pests, or unusual growths

New corals should be observed after arrival. If a coral begins melting, receding, or developing brown jelly-like tissue, act quickly and isolate or treat when appropriate. Read our coral quarantine guide and coral pests and predators guide for more help.

Common Challenges in Maintaining Live Corals

Most reef keepers eventually run into coral problems. The key is learning how to identify the likely cause before making random changes.

Corals Not Opening

Corals may stay closed because of shipping stress, pests, salinity swings, too much light, too much direct flow, poor water quality, fish irritation, or nearby coral aggression.

Corals Losing Color

Color loss may be caused by lighting stress, nutrient imbalance, bleaching, low nutrients, high nutrients, unstable alkalinity, or poor acclimation.

Tissue Recession

Tissue recession can come from alkalinity swings, direct flow damage, coral stings, pests, bacterial issues, shipping stress, or physical damage.

Algae Growing Around Corals

Algae can irritate coral tissue and prevent normal expansion. Nutrient balance, flow, manual removal, cleanup crew support, and stable maintenance can help.

Coral Bleaching

Bleaching can be triggered by too much light, rapid light increases, heat stress, low nutrients, salinity swings, alkalinity instability, or poor acclimation.

Maintaining a Reef Tank for Long-Term Coral Growth

Long-term coral success comes from repeated good habits. A reef tank does not need constant dramatic changes. It needs stable care, regular observation, and slow corrections when something begins to drift.

Good long-term habits include:

• Testing water consistently
• Recording test results
• Performing regular water changes
• Cleaning pumps and filtration
• Inspecting corals for pests or recession
• Feeding carefully
• Keeping nutrients measurable but controlled
• Replacing or cleaning mechanical filtration
• Watching coral behavior every day

In our experience, daily observation is one of the most underrated reef keeping skills. Corals usually show early warning signs before major problems happen.

Our Practical Live Coral Care Advice at Extreme Corals

At Extreme Corals, our practical advice is simple: start with healthy corals, place them correctly, keep the water stable, and do not rush changes. Corals usually do not need constant tinkering. They need a stable environment that matches their needs.

Our live coral care rules are:

• Buy corals that match your tank maturity and experience level.
• Keep salinity and alkalinity stable.
• Use proper lighting for the coral type.
• Use proper flow for the coral type.
• Do not strip nitrate and phosphate to zero.
• Do not let nutrients climb out of control.
• Acclimate new corals slowly.
• Inspect and quarantine when possible.
• Make corrections slowly unless there is a true emergency.

A thriving reef tank is built through patience. The more consistent the environment, the better chance your live corals have to grow and become long-term showpieces.

Related Live Coral Care Guides

If you are learning how to sustain live corals in a reef tank, these related guides and categories can help:

• Coral Care Guide - Learn the foundation of live coral care.
• Live Coral Care Guide - Understand soft corals, LPS corals, SPS corals, lighting, flow, and placement.
• Reef Tank Water Testing Guide - Learn what to test and why it matters.
• Best Reef Tank Lighting Guide - Match lighting to coral growth and color.
• Water Flow and Coral Health - Improve circulation and coral tissue health.
• Saltwater Aquarium Water Change Guide - Learn coral-safe water change habits.
• New Arrival Corals - Browse recently added live corals.
• Scott's Handpicked Corals - Explore standout corals selected for color and quality.

Shop Healthy Live Corals for Your Reef Tank

Sustaining live corals begins with good care, but it also begins with choosing healthy coral that fits your tank. Soft corals, LPS corals, SPS corals, Zoanthids, mushrooms, and collector pieces all have different needs. The best coral for your reef is the one that matches your lighting, flow, water stability, experience level, and placement plan.

Browse new arrival corals, new coral frags, new coral colonies, LPS corals, SPS corals, soft corals, Zoanthids, and Scott's Handpicked Corals at ExtremeCorals.com to find healthy corals for your reef aquarium.

Frequently Asked Questions About Sustaining Live Corals

Are live corals hard to keep in a reef tank?

Some live corals are beginner friendly, while others are advanced. Soft corals and many Zoanthids are often easier, LPS corals are usually moderate, and many SPS corals need more stable advanced reef conditions.

What do live corals need to survive?

Live corals need stable saltwater, proper lighting, appropriate flow, balanced nutrients, correct placement, and protection from pests, aggression, and rapid water chemistry changes.

What water parameters do live corals need?

Many reef tanks do well with temperature around 76-80°F, salinity around 1.024-1.026, pH around 8.1-8.4, alkalinity around 8-10 dKH, calcium around 400-450 ppm, and magnesium around 1250-1350 ppm.

Do live corals need strong lighting?

Some corals need strong lighting, but not all. SPS corals often need stronger light, many LPS corals prefer moderate light, and many soft corals and mushrooms do well in low to moderate lighting.

What flow is best for live corals?

The best flow depends on the coral type. SPS corals usually need stronger random flow, LPS corals usually need moderate indirect flow, and mushrooms and many soft corals often prefer lower to moderate flow.

Do live corals need feeding?

Many live corals are photosynthetic, but feeding can still help. LPS corals may accept small meaty foods, while SPS, soft corals, Zoanthids, and mushrooms often benefit from stable nutrients and fine suspended foods.

Why are my live corals not opening?

Corals may stay closed because of shipping stress, pests, poor water quality, salinity swings, too much light, too much flow, fish irritation, or nearby coral aggression.

Should I quarantine new live corals?

Quarantine is strongly recommended when possible. At minimum, inspect new corals carefully and dip when appropriate to reduce the risk of pests entering the display tank.

How do I prevent coral disease?

Prevent coral disease by maintaining stable water, avoiding tissue damage, quarantining or dipping new corals when appropriate, preventing pests, using proper flow, and acting quickly when tissue recession or brown jelly appears.

What is the best coral for beginners?

Many beginner reef keepers start with hardy soft corals, Zoanthids, mushrooms, Clove Polyps, or easier LPS corals once the tank is stable. The best choice depends on the tank’s light, flow, maturity, and maintenance routine.

About the Author

Scott Shiles is the owner of ExtremeCorals.com, which he has operated for over 25 years and is recognized as one of the early dedicated live coral websites on the internet. A lifelong reef keeper since 1984, Scott has decades of hands-on experience maintaining marine aquariums and previously owned and operated a brick and mortar aquarium retail store for 10 years, including five years alongside Extreme Corals. He holds a degree in Marine Biology and has personally selected and sold hundreds of thousands of live corals. An avid scuba diver who has explored reef systems around the world, Scott shares practical coral care and husbandry knowledge based on real world reef experience.