How to Frag Coral: Complete Guide to Coral Propagation

1. What is Coral Fragging?

Coral fragging (short for “fragmenting”) is the process of cutting or breaking a piece from a parent coral colony to create a new, genetically identical clone [1]. It is a form of asexual reproduction — the same method corals use naturally when storm damage breaks branches that reattach to new substrate [15]. Every frag is a genetic clone of the mother colony [14].

Fragging has become one of the most important skills in the reef keeping hobby. Reefers frag corals to share with friends and fellow hobbyists, to sell or trade for new species, to save a dying colony by rescuing healthy tissue, and to fill empty space in their tanks with proven genetics [1] [17]. Propagation through fragging also reduces pressure on wild coral reefs by making captive-bred corals more widely available [15].

Key Principle: Healthy parent colonies recover from fragging quickly and often grow faster afterwards, as the cut stimulates new growth — similar to pruning a plant [1] [14]. Only frag colonies that are healthy and well-established in your tank.

2. Essential Tools & Supplies

Having the right tools makes fragging safer for both you and the coral. The tool you need depends on the type of coral you’re cutting [4] [5].

Cutting Tools

Tool	Best For	Notes	Source
Bone Cutters	SPS LPS	Most versatile fragging tool — handles branches, Euphyllia heads, and thin skeleton	[4] [5]
Band Saw	LPS	The “Cadillac” for Euphyllia and thick-skeleton LPS — clean, precise cuts	[3] [4]
Razor Blades / Scissors	Soft	Sharp scissors or razor blades for leathers, mushrooms, and soft tissue corals	[5] [14]
Dremel with Diamond Wheel	SPS LPS	Excellent for plating SPS (Montipora) and splitting Euphyllia bases	[4] [12]
Scalpel	Soft LPS	Precision work on mushrooms, polyps, and delicate tissue	[5]

Supplies & Safety Gear

Mounting Supplies

Frag plugs (ceramic or aragonite) [1]
Frag discs (flat, for encrusting species) [1]
Super glue gel (cyanoacrylate — reef safe) [1] [13]
Reef-safe epoxy (for large/heavy frags) [1]
Rubber bands (for mushrooms & softies) [14]

Safety & Aftercare

Coral dip (CoralRx, Lugol’s, or Betadine) [7] [8]
Nitrile gloves (essential for zoanthids) [6] [9]
Eye protection / safety glasses [9]
Towels (to catch drips and protect surfaces) [1]
Separate container with tank water for working [1]

Pro tip: Keep a dedicated set of tools for fragging only. Cross-contaminating tools between tanks can spread pests and disease. Clean all tools with fresh water after each fragging session. [7]

3. Fragging Soft Corals

Soft corals are the easiest to frag and the best starting point for beginners [14]. They lack a hard calcium carbonate skeleton, which means you’re cutting through tissue only [5]. Most soft corals heal within approximately one week [14].

Leather Corals (Sinularia, Sarcophyton, Lobophytum)

Use sharp scissors or a razor blade to cut a section from the mother colony [14]. Cut underwater to minimize air exposure and stress [1]. Leathers will release a waxy mucus coating after being cut — this is normal and part of the healing process [14]. Attach frags to plugs with rubber bands or super glue [14]. The parent colony will heal over and may grow faster than before [1].

Mushroom Corals (Discosoma, Rhodactis, Ricordea)

Slice the mushroom in half through the mouth with a sharp razor blade, or score the oral disc with shallow cuts and return the mushroom to low flow — each scored section will develop into a new individual [14] [17]. For Ricordea, cut through the mouth to ensure each piece gets a portion of the oral disc [14]. Place cut pieces on rubble in a low-flow container; they will attach on their own within days [14]. See the mushroom corals care guide for the string method used on premium Bounce Ricordea morphs.

GSP & Xenia

Green Star Polyps grow on a purple mat — simply cut sections of the mat with scissors and attach to a new plug or rock [14]. Xenia can be cut at the stalk with scissors [14]. Both species are aggressive growers and among the easiest corals to propagate [15].

Zoanthids & Palythoa

Use a sharp chisel or bone cutters to remove chunks of rock with the zoanthid colony attached [14]. Do NOT try to peel zoanthids off rock — chisel the rock beneath them [14]. ALWAYS wear gloves and eye protection when handling any zoanthid or palythoa species due to palytoxin risk [6] [9] (see Section 8).

Healing time: Most soft corals recover fully within ~1 week [14]. Mushrooms may take slightly longer (1–2 weeks) to form new mouths after being split [17].

4. Fragging LPS Corals

LPS (Large Polyp Stony) corals have a hard calcium carbonate skeleton covered with fleshy tissue [3]. Fragging LPS requires cutting through this skeleton, which demands more robust tools and careful technique. Healing takes significantly longer — 4 or more weeks for most species [3].

Euphyllia (Hammer, Torch, Frogspawn)

Euphyllia are the most commonly fragged LPS corals. Use bone cutters or a band saw to cut between individual heads where the skeleton branches [3]. Cut well below where the tissue appears to end — the skeleton extends further than it looks [3]. A band saw provides the cleanest cuts and is preferred for wall-type Euphyllia [3] [4]. Branching varieties can often be snapped apart at natural junction points with bone cutters [3].

Duncan Corals (Duncanopsammia)

Duncans grow in branching formations. Snap or cut individual heads at the base of the branch using bone cutters [3]. They are relatively easy to frag for an LPS — individual heads separate cleanly at natural break points [3].

Candy Cane (Caulastrea)

Candy Cane corals grow in trumpet-shaped branches. Snap or cut individual branches apart using bone cutters [3]. The branches typically separate easily at their junction points [3].

Acan Lords (Micromussa)

A band saw is the best tool for Acans — cut between individual polyps through the shared skeleton [3]. The tissue will retract during cutting; this is normal. Make clean, decisive cuts to minimize tissue damage [3]. Acans are more sensitive than Euphyllia and take longer to recover [3]. Chalice corals require the most demanding technique — see the designer LPS guide for the paper-thin chalice fragging walkthrough.

DO NOT FRAG these LPS corals: Elegance coral (Catalaphyllia), Plate/Disc corals (Fungia), most Brain corals (Trachyphyllia), Lobophyllia, and Bubble corals (Plerogyra). These species have growth structures that do not separate into viable fragments, and cutting them typically kills the colony [3] [14].

Healing time: LPS corals typically need 4+ weeks to fully recover from fragging [3]. Euphyllia heads may take 2–4 weeks to re-extend tentacles fully [3]. Acans can take 6+ weeks [3].

5. Fragging SPS Corals

SPS (Small Polyp Stony) corals are generally straightforward to frag because most species grow in branching formations that are easy to clip [2]. The main challenge is keeping the frags clean and free of infection after cutting [2] [12].

Acropora

The most commonly fragged SPS coral. Use bone cutters to clip branches 1–2 inches long from the colony [2] [12]. Cut at branch junctions where natural branching points provide a clean break [2]. Frags should have at least ¾ inch of branch length for best survival [12]. Dip all Acropora frags immediately after cutting to prevent infection at the exposed skeleton [2].

Montipora

Branching Montipora can be clipped with bone cutters just like Acropora [2]. Plating Montipora requires a Dremel with a diamond cutting wheel to cut sections from the plate [2] [12]. Work quickly and dip the frag immediately — plating Montipora frags are more susceptible to tissue recession at cut edges [2]. See the Montipora care guide for species ID and the nudibranch pest threat.

Birdsnest (Seriatopora) & Stylophora

These thin-branched SPS corals are among the easiest to frag — branches can often be snapped by hand or clipped with bone cutters [2] [16]. Take cuttings from the tips for best coloration [16]. Both species are fast growers and excellent beginner SPS frags — see the PSP trio care guide for species ID, designer morphs, and the red bug pest threat.

SPS fragging tips from BRS: Make frags at least 1 inch long for best survival rate. Cut with clean, sharp tools — crushing the skeleton increases infection risk [12]. Always dip SPS frags after cutting [2]. Healing takes 1+ month for full encrustation of the cut base [2].

6. Mounting Methods

Proper mounting ensures your frag stays attached to its plug or disc while it heals and begins to encrust. The most common and reliable methods use cyanoacrylate super glue gel, reef-safe epoxy, or a combination of both [1] [13].

The Glue-Epoxy-Glue Layering Technique

Top Shelf Aquatics recommends a layered approach for the strongest bond [1]:

1

Apply Super Glue to the Plug

Dab a generous amount of cyanoacrylate super glue gel onto the frag plug surface [1]. Use gel formula only — liquid super glue runs off and won’t bond [13].

2

Dip in Tank Water

Briefly dip the glued plug into tank water — super glue cures on contact with water, creating a tacky bonding surface [1] [13].

3

Dry the Frag Base

Pat the cut base of the frag dry with a towel. Super glue bonds best to dry surfaces [1].

4

Press Together & Hold

Press the dry frag base firmly onto the glued plug and hold for 30–60 seconds [1]. The bond sets almost instantly in contact with moisture from the frag [13].

When to Use Epoxy

For large or heavy frags, use reef-safe epoxy as the primary adhesive and super glue gel on top to set the bond quickly [1]. Epoxy provides structural bulk and holds heavy frags that super glue alone cannot support [13]. Knead the epoxy until it reaches a uniform color before applying [1].

Alternative Mounting Methods

Rubber bands: Ideal for mushrooms and soft corals that won’t accept glue. Wrap the frag loosely to a plug or piece of rubble; remove the band once attached (usually 3–7 days) [14].
Bridal veil mesh: Lay mushroom frags on rubble inside a plastic container covered with mesh to keep them in place while they attach naturally [17].
Frag racks: Egg crate or commercial frag racks hold plugs in place at a consistent height in the tank for healing [1] [17].

7. Post-Frag Care & Dipping Protocols

Dipping frags after cutting is critical for preventing infection at the exposed skeleton and removing pests [7] [8]. The cut exposes the coral’s inner skeleton to bacteria and parasites, which can cause rapid tissue loss if left untreated [7].

Dipping Protocols

Dip Solution	Concentration	Duration	Best For	Source
Lugol’s Iodine	40 drops per gallon	5–7 minutes	SPS LPS	[8]
Betadine (Povidone-Iodine)	2–3 mL per liter	10–25 minutes	SPS LPS	[8]
Coral Rx	Per manufacturer instructions	~10 minutes	SPS LPS Soft	[7]

Too much iodine can damage or kill coral tissue. Always measure carefully and do not exceed recommended concentrations or soak times [8]. When in doubt, use less and monitor the coral’s response.

Recovery Placement

Low flow: Place frags in an area with reduced water flow to prevent them from being knocked off their plugs while the glue cures [1] [7].
Lower light: Start frags at the bottom half of the tank or under indirect lighting for the first 1–2 weeks, then gradually move up to their permanent position [7] [17].
Monitor daily: Watch for signs of tissue recession, brown jelly disease, or rapid tissue necrosis (RTN) at the cut site. If infection appears, re-dip immediately [7].
Maintain water quality: Keep parameters stable. Newly fragged corals are more sensitive to swings in alkalinity, temperature, and salinity [7] [12].

8. CRITICAL: Palytoxin Safety

DANGER — Palytoxin is one of the most toxic substances known to science. It is found in many zoanthid and palythoa coral species commonly kept in home aquariums. There is no known antidote for palytoxin poisoning [6] [9].

Palytoxin is so potent that “6 grams of palytoxin would be enough to kill 1 billion mice” [6]. It is the second most toxic natural substance known, with an LD₅₀ of just 0.15 μg/kg in mice [9]. Human exposure occurs through skin contact, inhalation of vapors (from boiling or burning), or contact with eyes or mucous membranes [6] [9].

Research finding: A study tested zoanthid colonies purchased from fish stores and found that 4 out of 15 colonies contained highly toxic levels of palytoxin [11]. You cannot visually identify which species contain palytoxin — even common, inexpensive zoanthids can be extremely toxic [6] [11].

The CDC has documented multiple cases of palytoxin poisoning in reef hobbyists, including cases requiring hospitalization from handling zoanthids without gloves and from inhaling steam when placing hot rocks with attached zoanthids in boiling water [10].

Mandatory Safety Rules for Zoanthids & Palythoa

1

ALWAYS Frag Underwater

Never cut zoanthids in open air. Perform all cutting work in a container of tank water to prevent toxin from becoming airborne [6] [9].

2

ALWAYS Wear Gloves & Eye Protection

Palytoxin absorbs through skin and is especially dangerous if it contacts your eyes [6] [9]. Wear nitrile gloves and safety glasses whenever handling any zoanthid or palythoa species.

3

NEVER Boil, Burn, or Heat Zoanthids

Boiling water with zoanthids releases palytoxin as aerosol vapor. Multiple hospitalization cases have resulted from boiling live rock with zoanthids attached [10] [9]. Never use a heat gun, flame, or boiling water near any zoanthid species.

4

Wash Hands Thoroughly After Handling

Even with gloves, wash your hands and forearms with soap and water immediately after any contact with zoanthids [9]. Do not touch your face, eyes, or mouth during or after handling.

Symptoms of palytoxin exposure include: chest pain, difficulty breathing, rapid heart rate, muscle pain, nausea, and in severe cases, respiratory failure [9] [10]. If you experience any symptoms after handling zoanthids, seek immediate medical attention and tell the doctor you may have been exposed to palytoxin. Bring any information about the coral species if possible.

Remember: There is NO way to tell which zoanthids are toxic by looking at them. Treat ALL zoanthid and palythoa species as potentially lethal [6] [11]. The safety precautions above are not optional — they are essential for your health.

9. Species-Specific Quick Reference

A quick-lookup table covering the most commonly kept corals and how to frag them. Difficulty rated 1–5 (1 = easiest) [1] [2] [3] [14].

Species	Type	Tool	Difficulty	Frag-ability	Healing Time	Notes
Acropora	SPS	Bone cutters	2	Easy	1–2 months	Clip branches at junctions; dip after [2]
Montipora (branching)	SPS	Bone cutters	2	Easy	1–2 months	Same as Acropora branches [2]
Montipora (plating)	SPS	Dremel	3	Moderate	1–2 months	Diamond wheel; watch for edge recession [2] [12]
Birdsnest (Seriatopora)	SPS	Bone cutters / snap	1	Easy	2–4 weeks	Fragile branches snap easily [2] [16]
Stylophora	SPS	Bone cutters	1	Easy	2–4 weeks	Fast grower; great beginner SPS frag [2]
Hammer / Torch / Frogspawn	LPS	Bone cutters / band saw	3	Moderate	4–6 weeks	Cut between heads; band saw for wall types [3]
Duncan	LPS	Bone cutters	2	Easy	3–4 weeks	Snap individual heads at branch base [3]
Candy Cane (Caulastrea)	LPS	Bone cutters	2	Easy	3–4 weeks	Branches separate cleanly [3]
Acan Lords (Micromussa)	LPS	Band saw	4	Moderate	6+ weeks	Cut between polyps; slow recovery [3]
Leather (Sinularia / Sarcophyton)	Soft	Scissors / razor	1	Easy	~1 week	Cut underwater; mucus release is normal [14]
Mushrooms (Discosoma)	Soft	Razor blade	1	Easy	1–2 weeks	Slice in half or score; self-attach to rubble [14]
Ricordea	Soft	Razor blade	2	Easy	1–2 weeks	Cut through mouth for viable pieces [14]
GSP (Green Star Polyps)	Soft	Scissors	1	Easy	3–5 days	Cut mat sections; aggressive grower [14]
Xenia	Soft	Scissors	1	Easy	3–5 days	Cut at stalk; may spread uncontrollably [14] [15]
Zoanthids / Palythoa	Soft	Chisel / bone cutters	2	Easy	~1 week	PALYTOXIN RISK — gloves + goggles mandatory [6] [9]
Elegance (Catalaphyllia)	LPS	—	5	Don’t	—	Single polyp; cannot be divided [3]
Fungia (Plate Coral)	LPS	—	5	Don’t	—	Single polyp; free-living — do not cut [3]
Brain Coral (Trachyphyllia)	LPS	—	5	Don’t	—	Single polyp; cutting kills the colony [3] [14]
Bubble Coral (Plerogyra)	LPS	—	5	Don’t	—	Inflated vesicles make cutting impractical [3]

10. Frequently Asked Questions

How big should a coral frag be?

For SPS corals, frags should be at least 1 inch (2.5 cm) long for best survival rates [12]. BRS recommends at least ¾ inch as a minimum [12]. For LPS corals like Euphyllia, each frag should include at least one complete head with sufficient skeleton below it [3]. Larger frags generally recover faster and have higher survival rates [1].

When is the best time to frag corals?

Frag when the parent colony is healthy and actively growing [1]. Avoid fragging during or immediately after parameter swings, disease outbreaks, or other stressful events [7]. Many reefers prefer to frag right before a scheduled water change, so fresh saltwater helps the healing process [17].

Should I dip corals before or after fragging?

After fragging is most important — the cut site is an open wound vulnerable to infection [7] [8]. However, some experienced reefers also dip before to remove pests from the parent colony first [7]. For SPS corals, BRS strongly recommends a post-frag dip every time [2].

Is super glue safe for aquariums?

Yes. Cyanoacrylate super glue gel is completely reef safe once cured [1] [13]. It cures almost instantly on contact with water and forms an inert bond. Use gel formula only — liquid super glue runs off and won’t hold. Many reefers use standard store-bought super glue gel; specialty “coral glue” products are the same compound at a higher price [13].

Can I frag a coral that is stressed or bleaching?

Generally no — fragging adds stress to an already stressed organism [7]. The one exception is “rescue fragging”: if a colony is actively dying (e.g., RTN spreading from the base), cutting away the healthy portion above the infection line can save that tissue [7] [17]. In this case, speed matters more than ideal conditions.

Are zoanthids dangerous to handle?

Yes — potentially extremely dangerous. Many zoanthid and palythoa species contain palytoxin, one of the most toxic natural substances known [6] [9]. There is no known antidote [9]. The CDC has documented hospitalization cases from hobbyists handling these corals [10]. You cannot tell which zoanthids are toxic by appearance — always wear gloves and eye protection, and never boil or burn them [6] [11]. See Section 8 for full safety protocols.

References

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