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The three hobby groups
Reef aquarists sort photosynthetic corals into three practical groups. The categories are hobby shorthand rather than strict biology, but they line up well with care needs.
- Soft corals lack a rigid stony skeleton. They're usually the hardiest.
- LPS (large polyp stony) corals build calcium carbonate skeletons and have large, fleshy polyps.
- SPS (small polyp stony) corals build skeletons with tiny polyps and are usually the most demanding.
Zoanthids, mushrooms (corallimorphs) and gorgonians are often grouped with softies even though biologists place them in separate orders. Non-photosynthetic corals (NPS) are a separate, advanced category that depends entirely on feeding.
Care at a glance
| Soft corals | LPS | SPS | |
|---|---|---|---|
| Difficulty | Easy | Easy to moderate | Moderate to hard |
| Light (PAR) | ~50–150 | ~75–200 | ~150–500 |
| Flow | Low to moderate | Moderate, indirect | Strong, turbulent |
| Big 3 importance | Low | Moderate | High, especially alkalinity stability |
| Nutrients | Tolerant of higher | Tolerant; often benefit from feeding | Low and stable |
| Main risk | Chemical warfare, overgrowth | Sweeper tentacles, brown jelly | RTN/STN from swings, pests |
See the lighting guide for PAR details and the Big 3 guide for chemistry.
Soft corals
Common examples: leather corals (Sarcophyton, Sinularia), Kenya trees (Capnella), pulsing xenia, green star polyps, toadstools, and colt corals. Mushrooms (Discosoma, Rhodactis, Ricordea) and zoanthids are usually lumped in.
Care. Softies tolerate a wide range of light, flow and nutrients and often prefer somewhat "dirtier" water than SPS. Many leathers periodically shed a waxy film and stay closed for days. That's normal.
Watch out for. Many soft corals release terpenoid compounds that irritate or inhibit other corals ("chemical warfare"). Running activated carbon (GAC) helps. Some species, like GSP, xenia and some mushrooms, spread aggressively and can overgrow rock. Placing them on an isolated rock is a common trick. Zoanthids and especially Palythoa can contain palytoxin, which is dangerous to people. Wear gloves and eye protection when handling them, and never boil, scrub or pressure-wash rock covered in them.
LPS corals
Common examples: hammer, frogspawn and torch corals (hammers and frogspawn are now in Fimbriaphyllia, torches remain Euphyllia), acans (Micromussa), Blastomussa, Lobophyllia, chalices, brain corals (Favia, Trachyphyllia), duncans, candy cane (Caulastraea), bubble coral (Plerogyra) and plate corals (Fungia).
Care. Moderate light and moderate, indirect flow. Too much flow keeps fleshy polyps from inflating. LPS build skeletons, so they consume alkalinity and calcium and need reasonably stable Big 3 values. Many feed eagerly. Target feeding with small meaty foods such as mysis, or pellet coral foods, once or twice a week can speed growth noticeably.
Watch out for. LPS are some of the most aggressive corals in the tank. Many extend sweeper tentacles at night that can reach several inches and sting neighbors, so leave plenty of space. Chalices and some brains also digest neighbors with mesenterial filaments. Several sand-dwelling LPS (plate corals, open brains) belong on the sand bed, not on rock. Brown jelly disease is a known risk with damaged Euphyllia. Remove decaying tissue and isolate the colony if you see brown, slimy tissue.
SPS corals
Common examples: Acropora, Montipora (including digitata), Stylophora, Pocillopora, Seriatopora (birdsnest), and Porites.
Care. SPS want strong light, strong and turbulent flow, and very stable chemistry. Alkalinity swings are particularly linked to SPS tissue loss. Experienced keepers recommend waiting until a tank is mature (often 6–12 months or more) before adding Acropora. Montipora, birdsnest and Stylophora are more forgiving first SPS.
Watch out for. RTN and STN, burnt tips under high alkalinity with very low nutrients, and pests such as Acropora-eating flatworms, red bugs and Montipora-eating nudibranchs. Dip and inspect every new SPS. See the pests guide.
Good first corals
- Softies: mushrooms, toadstool and finger leathers, Kenya tree, zoanthids (with gloves), GSP on an island rock.
- LPS: duncan, candy cane, hammer or frogspawn (with room), acan, blastomussa.
- First SPS: Montipora capricornis or digitata, birdsnest, Stylophora.
Buying aquacultured frags rather than wild colonies is easier on wild reefs and the corals are usually already adapted to aquarium conditions. See our conservation guide.
Adding new corals
- Acclimate temperature by floating the bag for 15–30 minutes, then match water slowly. Corals are less sensitive to salinity differences than fish, but keep it close.
- Dip in a reef coral dip product (made according to the manufacturer's directions) to dislodge pests. Inspect closely for flatworms, eggs, nudibranchs and hitchhikers, especially on SPS.
- Cut or clean the base of frag plugs if they carry algae, aiptasia or eggs.
- Place low and shaded, then move up over a couple of weeks.
- Quarantine if you can. A coral QT for several weeks is the only reliable way to keep pests whose eggs survive dips out of the display.
Placement and spacing
Put light-hungry SPS high and in strong flow, LPS mid-level or on the sand with moderate flow, and most softies and mushrooms lower or in lower-flow areas. Leave at least several inches between aggressive LPS and anything else, and plan for growth. A small coral today can cover a rock in a year. Secure frags with reef-safe cyanoacrylate gel or epoxy so they can't fall.
Fragging
Fragging means cutting a coral into pieces to propagate it. Soft corals can be cut with a scalpel or scissors. Branching SPS can be snapped or cut with bone cutters. Many LPS need a saw to cut between heads. Use gloves and eye protection, keep cuts clean, glue frags onto plugs, and place them in moderate light and flow while they heal. Trading frags with local reefers is a big part of the hobby and reduces demand on wild collection.
Reading coral health
- Polyp extension is a good daily comfort signal.
- Color shifts: pale or white suggests light, temperature or chemistry stress. Brown suggests high nutrients or low light.
- Tissue recession from the base (STN) or a fast peel (RTN) in SPS is an emergency. Check alkalinity, temperature and pests right away.
Most coral problems trace back to a sudden change. Log your tests and changes so you can find the cause.
Flow and feeding across coral types
Flow is easy to underestimate. Water movement delivers food and oxygen, removes waste and mucus, and keeps detritus from settling on tissue. A common rule of thumb is a total turnover from powerheads and return of roughly 20–50 times the tank volume per hour for mixed reefs, and more for SPS-heavy systems. Random or alternating flow from wavemakers is better than a single strong stream aimed at a coral, which can tear tissue.
Feeding needs vary as much as flow. Soft corals and SPS mostly take up dissolved and very fine particulate food, so broadcast feeding of fish and occasional fine coral foods are usually enough. LPS have large mouths and catch meaty foods. NPS need daily or near-daily target feeding. Whatever you feed, watch nitrate and phosphate, and adjust export accordingly. See the nutrient guide.
Summary
Start with softies and hardy LPS while your tank matures, give LPS room to sting, and wait for real stability before Acropora. Match light and flow to each group, dip and inspect every new coral, and buy aquacultured frags when you can.
Frequently asked questions
What is the difference between SPS and LPS corals?
Both build stony skeletons. SPS have tiny polyps and usually need strong light, strong flow and very stable chemistry. LPS have large fleshy polyps and are generally more forgiving.
What are the easiest corals for beginners?
Mushrooms, leathers, Kenya trees, zoanthids and hardy LPS such as duncans and candy canes are commonly recommended first corals.
When can I add SPS corals to a new tank?
Many keepers wait until the tank is mature, often 6 to 12 months or more, with stable alkalinity, before adding Acropora. Montipora and birdsnest can go earlier.
Do corals need to be fed?
Photosynthetic corals get much of their energy from light, but many LPS benefit from target feeding once or twice a week. Non-photosynthetic corals must be fed frequently.
Are zoanthids dangerous?
Some zoanthids and especially Palythoa contain palytoxin. Wear gloves and eye protection, and never boil or pressure-wash rock that has them.
Open the free dosing calculator
More reef science guides
- Alkalinity, calcium & magnesium
- Nitrogen cycle & cycling
- Nitrate & phosphate
- Salinity & RO/DI
- Lighting & PAR
- Pests & diseases
- Reef conservation & science
- Coral symbiosis & Symbiodiniaceae
- Coral bleaching science
- Ultra-low nutrient research
- Ocean acidification & calcification
- Coral restoration & microfragmentation
- ICP testing & trace elements
Ranges are common hobby targets compiled from reef chemistry literature (including Randy Holmes-Farley's articles), hobby consensus and manufacturer documentation. They're not rules. Last reviewed 2026-10-15.