Coral Fragging Basics: Tools, Technique, and Healing for Soft, LPS, and SPS

Fragging is the process of cutting a piece of coral off a colony, healing it, and mounting it on a frag plug or rock. It is how aquaculture works, how the hobby produces affordable corals at scale, and how a reef keeper turns a single $80 acropora into a propagation chain that pays for itself. The technique varies by coral category: soft corals are forgiving and easy, LPS demands careful skeleton cuts, and SPS requires precise breaks and quick remounting. This guide covers the tool kit, the cut technique for each category, the dip protocol that prevents infection, and the 4 week healing schedule that produces frags ready to swap or sell.

When to frag

Two reasons to frag a coral: aesthetic (the colony has outgrown its space) and propagation (you want to expand stock, trade, or sell).

The timing rules:

• Coral must be in the tank at least 4 to 6 weeks before first frag
• Coral must be growing visibly (new polyps, branch tips, encrusting tissue)
• Skip fragging during temperature swings, after a water change of more than 30 percent, or within 48 hours of any major tank event
• Most corals tolerate 1 frag per 3 months. Aggressive fragging (every 4 weeks) stresses the colony and slows growth.

The fragging tool kit

The basic kit runs $50 to $80:

• Coral cutters (bone shears): heavy-duty side cutters for LPS and SPS branches, $15 to 30
• Diamond band saw or Gryphon C-40 saw (optional): for chalices, brains, and other LPS that need a flat cut, $250 to 350
• Scalpel with #11 blades: for soft corals, $5
• Razor blades: for zoanthids and mushrooms
• Frag plugs (ceramic, 1 inch and 1.5 inch): buy in bulk
• Frag racks: magnetic or grid, $20 to 40
• Cyanoacrylate gel (Instant Krazy Glue Gel): the standard mounting adhesive, $4 per tube
• Coral dip (Coral Rx or Bayer): $20 to 30
• Two small containers: one for dip, one for rinse, any 4 oz cup works
• Tweezers: for handling small frags
• Paper towels: for blotting cut surfaces

Soft coral fragging

The easiest category. Soft corals heal in 2 to 3 weeks and tolerate aggressive cuts.

Zoanthids and palythoa

1. Identify the mat of polyps to be cut. Look for at least 3 to 5 polyps per frag.
2. Slide a razor blade under the mat where it meets the rock or plug.
3. Lift the mat away from the substrate in one piece.
4. Cut the mat into pieces with 3 to 5 polyps each.
5. Dip for 5 to 10 minutes in Coral Rx (zoanthids commonly carry zoa pox, sundial snails, and Asterina starfish).
6. Glue the mat to a frag plug with cyanoacrylate gel. Place glue on the plug, press the mat onto it for 30 seconds, return to tank.

CRITICAL: Zoanthids and palythoa carry palytoxin, one of the most toxic substances on earth. Wear nitrile gloves and safety glasses. Never frag zoas near children or pets.

Mushrooms (Discosoma, Ricordea, Rhodactis)

1. Cut the mushroom in half through the mouth with a scalpel.
2. Cut each half in half again to make 4 pie slices.
3. Place the pie slices on a frag plug with rubble around them to keep them in place (do not glue mushrooms, they detach).
4. Return to low-flow area of the tank.
5. Each pie slice grows into a full mushroom in 6 to 10 weeks.

Leathers (toadstool, finger leather, devil’s hand)

1. Cut a 1 to 2 inch tip off a branch or polyp lobe with a scalpel.
2. Suture or rubber-band the frag to a frag plug (cyanoacrylate does not bond to soft tissue well).
3. Let the frag sit in low flow for 2 to 3 days until tissue attaches to the plug.
4. Once attached, remove the rubber band.

GSP and clove polyps

These spread on rock as a mat. Cut a piece of rock with mat attached and glue the rock to a plug.

LPS coral fragging

LPS sits between soft and SPS. Requires a clean skeleton cut and longer healing.

Hammer, frogspawn, torch (Euphyllia)

1. Identify a branch with at least 2 to 3 heads.
2. Use bone shears to snap the branch above a junction (where two heads meet).
3. Dip the frag for 5 minutes in Coral Rx (Euphyllia commonly carries brown jelly disease bacteria).
4. Glue the cut skeleton end to a frag plug.
5. Place in low-medium flow, medium light, for the first 2 weeks. Move to final position over the next 2 weeks.

Healing time: 4 to 6 weeks for full polyp extension and visible new tissue at the cut.

Acan, chalice, brain

These require a flat saw cut through the skeleton, not a clean snap. Use a diamond band saw or rotary tool with a diamond blade.

1. Mark the cut line outside any polyp mouths.
2. Make a straight cut through the skeleton. Keep the coral wet during cutting if possible.
3. Dip the frag for 5 minutes.
4. Glue the flat side to a plug.
5. Place in low light, low flow for 2 weeks before moving toward final position.

Healing time: 6 to 10 weeks for full tissue regeneration and encrusting.

Plate corals (Fungia, Heliofungia)

Plate corals can be cut radially with a band saw into pie slices. Each slice regenerates a full mouth in 8 to 12 weeks.

SPS coral fragging

The most technical category. SPS heals slowly, demands clean cuts, and benefits from a dedicated frag system.

Acropora

1. Identify a branch with 2 to 4 sub-branches off the main stem.
2. Use bone shears to cleanly snap the branch as close to a junction as possible.
3. Dip the frag for 5 to 10 minutes in Coral Rx or Bayer.
4. Rinse in clean saltwater.
5. Dab the cut end on a paper towel for 1 to 2 seconds (just enough to remove water, do not let it dry out).
6. Apply cyanoacrylate gel to a frag plug.
7. Press the cut end into the glue for 30 seconds.
8. Return to the tank, placing the frag in medium light, medium flow.

Healing time: 4 to 8 weeks for tissue to grow over the cut and onto the plug. Full encrusting at 10 to 12 weeks.

Montipora capricornis (plating)

1. Use bone shears to break off a piece along the edge, 1 to 2 inches across.
2. Dip for 5 minutes.
3. Glue the broken edge to a plug.
4. Place horizontally in medium light.

Stylophora, Pocillopora, Seriatopora (birds nest, etc.)

These are extremely easy SPS to frag. They snap cleanly between branches and heal in 3 to 5 weeks.

The dip protocol

Every fragged coral should be dipped before remounting. Dipping kills hitchhiking pests (red bugs, flatworms, zoa eating nudibranchs, montipora-eating nudibranchs, parasitic copepods, snails) and bacteria that would otherwise infect the cut.

Standard dip protocol:

1. Mix dip per manufacturer instructions in 4 oz of tank water in a small cup
2. Place the frag in the dip
3. Agitate gently for 5 to 10 minutes (Bayer 5 minutes, Coral Rx 10 minutes)
4. Lift the frag out and inspect for dislodged pests
5. Rinse in a second cup of clean tank water
6. Mount and return to tank

A second dip 7 to 10 days later kills pests that hatched from eggs that survived the first dip.

The healing schedule

Week 1: low flow, low light. Watch for tissue recession or mucus production. If the frag retracts polyps for more than 48 hours, something is wrong (usually pest, infection, or shock).

Week 2: polyps should extend. The cut should look like fresh tissue, not skeleton.

Week 3 to 4: tissue starts to encrust onto the plug. The frag begins to look like a small colony.

Week 6 to 8: full polyp extension, visible new growth at the tips (SPS) or new heads (LPS, soft).

Week 10 to 12: the frag is fully encrusted, healed, and ready to be moved, traded, or sold.

For coral husbandry, see our coral care guide for soft, LPS, and SPS and the reef tank lighting guide. The /methodology page covers our coral trial protocol.

Frequently asked questions