What is an LPS Coral?
LPS coral is the name given to the group of coral species that have a stony skeleton, made from calcium carbonate, and large fleshy polyps. Many of the popular LPS coral species look a bit like a cross between a small polyp stony coral and a soft coral.
LPS Coral Types
The most popular LPS coral types are:
- Hammer
- Torch
- Frogspawn
- Bubble
- Acans
- Duncans
- Lobos
- Candy Cane
- Trumpet coral
- Brain corals
- Blastomussa
- Elegance Coral
- Fungia plate corals
- Gonipora Flower Pot
- Favia
- Favites
- Galaxea
Or alternatively, you can check out this guide to the 14 Best LPS Corals for Beginners, which will help you narrow down the list.
Proper care
It is sometimes dangerous to provide generalizations about large groups of coral species awkwardly lumped together as LPS coral, but in many instances, these corals are from deeper, slower moving water that is even sometimes turbid (the water is murky). They typically require low-to-moderate lighting and flow and are sometimes capable of feeding directly on meaty foods.
Why do LPS corals prefer lower light and flow? In their natural habitats, many LPS corals are found in deeper or more sheltered reef zones, where sunlight is less intense and water movement is gentler. Their large, fleshy polyps are adapted to capture food particles from the water and can be easily damaged by strong currents or excessive light. Too much light can cause bleaching, where the coral expels its symbiotic zooxanthellae, resulting in pale or white tissue and potentially leading to death. Excessive flow can physically tear or retract polyps, inhibit feeding, and cause tissue recession.
What happens if lighting or flow is not appropriate? If LPS corals receive too much light, you may observe bleaching, faded coloration, or tissue loss. If flow is too strong, polyps may remain retracted, become torn, or produce excessive mucus as a stress response. On the other hand, too little flow can result in detritus buildup and poor gas exchange, which may also stress the coral.
Balancing care in a mixed reef: Different LPS species may have slightly different preferences for light and flow, so placement in a mixed reef requires observation and adjustment. For example, Euphyllia species (Hammer, Torch, Frogspawn) often tolerate moderate flow, while others like Trachyphyllia prefer gentler conditions. Monitor each coral for signs of stress—such as receding tissue, excessive mucus production, or polyp bailout (where polyps detach from the skeleton)—and adjust placement as needed. In a mixed tank, it may be necessary to compromise or create microhabitats with varied flow and lighting.
Safe handling tip: An LPS coral should never be removed from the aquarium while the polyps are inflated, because inflated, fleshy polyps may tear on their own skeleton when removed from the water. This is due to the delicate tissue stretching over sharp skeletal ridges. To safely move or acclimate an LPS coral, gently encourage the polyps to retract first—this can be done by gently wafting water over the coral or briefly dimming the lights to signal nighttime conditions. Wait until the polyps have withdrawn before lifting the coral from the water.
Use caution when placing LPS corals near other corals—many LPS species have long sweeper (stinging) tentacles, and will battle with neighbors that are too close. Sweeper tentacles are specialized structures that extend well beyond the visible body of the coral and serve as a defense mechanism, allowing the coral to compete for space by stinging or damaging nearby corals. The length and aggressiveness of sweeper tentacles can vary greatly between species and even among individual colonies. Some LPS corals, such as Galaxea and Euphyllia, are particularly notorious for long, potent sweepers.
Operational consequences of aggression: Aggressive interactions can lead to tissue damage, stunted growth, or even the death of neighboring corals. In addition to physical stinging, some LPS corals release chemicals (allelopathy) that inhibit or damage other corals. Signs of aggression-related stress include unexplained tissue loss or recession on adjacent corals, localized bleaching, or the appearance of necrotic (dead) tissue.
Managing aggression: To minimize problems, provide adequate spacing between LPS corals and their neighbors—often several inches or more, depending on the species. Observe corals at night, when sweeper tentacles are most likely to be extended. If aggression is observed, consider rearranging corals, using physical barriers, or relocating sensitive species. Regular monitoring is key to catching problems early.
Since large polyp stony corals have a calcified external skeleton, it is important to monitor alkalinity and dissolved calcium levels. Persistently low calcium can slow calcification and coral growth, and a prolonged imbalance may compromise coral health, especially when alkalinity or magnesium is also unstable. Sufficient levels can sometimes be achieved with the regular use (and exchange) of saltwater made from a high-quality salt mix, although supplementation may be necessary to maintain optimal calcium/alkalinity levels in between water changes. Arguably, the more involved managing of water chemistry is one of the things that makes large polyp stony corals (LPS) more difficult to keep than their soft-bodied cousins.
Understanding calcium, alkalinity, and magnesium: These three parameters are closely linked in reef chemistry. Calcium and alkalinity are both required for skeletal growth, but if either is out of balance, corals may struggle to build or maintain their skeletons. Magnesium acts as a buffer, helping to prevent unwanted precipitation of calcium carbonate and stabilizing both calcium and alkalinity levels. Driving calcium or alkalinity too high can cause precipitation (cloudiness or crusty deposits), while persistently low or unstable levels can contribute to stunted growth or tissue recession. If you notice unstable levels or poor coral growth, check all three parameters and adjust as needed. Regular testing for magnesium, in addition to calcium and alkalinity, is recommended for diagnosing and maintaining a healthy environment.
There is a lot more to learn about the care requirements for each specific type of LPS coral. You can dig deeper in each of the guides above, or check out the 14 Best LPS Corals for Beginners to help you narrow down the list.
Feeding
Don’t forget that corals are animals. They do have symbiotic dinoflagellates, called zooxanthellae, that convert light energy into food, like plants, and provide them with some nutrition, but LPS coral species have large fleshy polyps, designed by nature to capture and eat food. They will do best in your saltwater aquarium if you feed them regularly with soft, meaty foods.
Feeding trade-offs and risks: While regular feeding can promote growth and vibrant coloration in LPS corals, it also increases the nutrient load in your aquarium. Overfeeding can lead to elevated nitrate and phosphate levels, which may cause algae outbreaks or harm sensitive corals and invertebrates. Signs of overfeeding include persistent algae growth, cloudy water, or rising nutrient test results. To avoid these problems, adjust feeding frequency and portion size based on how quickly your corals consume food and how your nutrient levels respond. Some LPS corals may not accept food, or may be outcompeted by fish and invertebrates, so observe each coral’s feeding response and adjust your approach as needed.
Testing
If you want to keep LPS corals, you will want to test for ammonia and nitrate, to be sure that water quality remains high and that there is not an accumulation of nitrate or rapid increase in ammonia due to decay. Since these corals actively use calcium and alkalinity to build their calcium carbonate skeletons, you will also want to test calcium, alkalinity, and magnesium periodically. Record results over several days in your Reef Journal so you can see trends rather than reacting to a single reading. This helps you maintain balanced reef tank parameters that support LPS coral growth.
Repeated tests under consistent conditions can help you estimate how quickly your LPS coral and SPS coral species are using calcium and alkalinity. For balanced supplementation, use measured alkalinity demand as the primary guide because short-term calcium changes can be difficult to distinguish from normal testing variation.
If kalkwasser fits your system, prepare it separately, allow undissolved powder to settle, and dose only the clear kalkwasser solution slowly. Tune the dose to measured alkalinity demand while monitoring both alkalinity and pH, and never add more kalkwasser solution than the tank’s freshwater evaporation can accommodate. Use fail-safes, such as a limited reservoir and a properly configured dosing or top-off controller. Never add kalkwasser powder directly to the aquarium or use kalkwasser for a large one-time correction. Because kalkwasser raises calcium and alkalinity together, use a carefully measured calcium-only supplement instead if calcium alone is low while alkalinity is already on target. Continue monitoring magnesium and the other reef tank parameters as you make gradual adjustments.
How to frag LPS coral species
An excerpt from How to Frag Corals
LPS corals can range from difficult to frag to relatively easy, depending on how easily you can make the cut in between the large, fleshy polyps. Many of the LPS Corals have two growth forms—difficult-to-frag wall growth forms and easy-to-frag branching growth forms. The difference in fragging risk comes down to polyp structure and tissue connectivity: wall corals have continuous tissue stretched over a large skeleton, making it hard to cut without injuring the polyps, while branching forms have more discrete polyps on separate branches, allowing for cleaner cuts.
I don’t recommend that you try to frag any of the wall variety corals (like the Hammer Corals that grow in a wall formation), the LPS corals sometimes called Open Brain Corals (Trachyphyllia species), or any species that grows as a mass or ball/brain shape, unless you have quite a lot of experience fragging corals. Your coral could suffer an infection and die as a result of fragging. In my opinion, this risk is highest with LPS Corals and particularly those without any good, safe place to cut them without risking a tear right through the polyps.
Many of the branching varieties of LPS Corals are the easiest corals to frag in this category because the branching growth form allows you to cut an entire branch without risking damage to the rest of the coral. Torch (Euphyllia glabrescens), Hammer (Euphyllia ancora), Frogspawn (Euphyllia divisa), Candy Cane (Caulastrea furcata), Trumpet (Caulastrea curvata), Duncans (Duncanopsammia axifuga) are all examples of corals that grow in a branching form and can be fragged relatively easily.
Fragging techniques
Fragging branching LPS Coral species is a little bit different from fragging Soft Coral species. The bases of LPS Corals are stony, and you can’t slice through them with a knife. A branching LPS Coral is best fragged using the Snapping method with a set of bone cutters (if you have them) or with the Sawing method. Generally, you want to aim for the lowest part of the branch you can safely cut through and try to make the cut nice and flat so that your frag will stand up once attached.
Minimizing fragging risk: Always use sterilized tools to reduce the risk of infection. Handle corals gently to avoid tearing tissue. After fragging, place the new frags in a low-flow, low-light area to recover. Monitor for complications such as tissue recession, excessive mucus, polyp bailout (where polyps detach from the skeleton), or signs of infection (cloudy tissue, foul odor). If problems arise, improve water quality, reduce stress, and consider using a coral dip to prevent or treat infection. Early intervention can improve fragging success rates.
Attachment techniques
A branching LPS Coral species can be attached to a coral plug or piece of live rock with the Glue method, using cyanoacrylate glue. The glue will generally create a fairly strong bond between the coral skeleton and the rockwork without damaging the coral.
Want to learn more?
For more information about how to frag corals, check out the article series here.
A great resource to learn more about LPS corals is the book, Aquarium Corals: Selection, Husbandry, and Natural History, by Eric H. Borneman. I have worn out the spine of my copy of this book. There are about 500 pages of amazing content and pictures about LPS coral, SPS corals, soft corals, and more. I recommend you pick up a copy to add to your (hopefully) growing library.
Written by Albert B. Ulrich III–author of The Reef Aquarium Series of books: The New Saltwater Aquarium Guide, How to Frag Corals, 107 Tips for the Marine Reef Aquarium and Reef Journal