One of the most rewarding aspects of reef keeping is watching corals grow and flourish over time. What begins as a small frag can eventually develop into a stunning colony, adding colour, movement, and life to your aquarium. But what happens when those corals become so healthy that they outgrow their space?
That’s where coral fragging comes in.
Coral fragging is the process of carefully cutting or dividing corals to create new colonies. It has become a cornerstone of the modern reef-keeping hobby, allowing aquarists to propagate their favourite corals, share them with fellow hobbyists, and maintain healthy growth within their aquariums.
Whether you’re interested in creating space for future coral growth, trading with friends, or simply learning more about coral husbandry, this guide will introduce you to the fascinating world of coral fragging.
What Is Coral Fragging?
The term “frag” is short for fragment.
Coral fragging involves removing a small section of a healthy coral colony and attaching it to a frag plug, rock, or mounting surface where it can continue to grow independently.
In many ways, coral fragging is similar to taking cuttings from a garden plant.
Given the right conditions, the new fragment will heal, encrust, and eventually develop into a fully formed colony.
Many coral species naturally reproduce this way on wild reefs, where storms and wave action can break off pieces that settle elsewhere and continue growing.
Why Frag Corals?
There are several reasons why reef keepers choose to frag their corals.
Control Coral Growth
Many corals can grow surprisingly quickly under ideal conditions.
Without occasional pruning, fast-growing species can:
- Shade neighbouring corals
- Compete for space
- Restrict water flow
- Alter the aquascape
Fragging helps keep growth under control while maintaining the overall balance of the reef.
Create New Colonies
A single healthy coral colony can produce multiple frags over time.
This allows hobbyists to:
- Fill out their reef aquascape
- Create backup colonies
- Experiment with placement
Trade and Share
Fragging has helped create a thriving reef-keeping community.
Many hobbyists exchange frags with friends, local reef clubs, or fellow aquarists, allowing everyone to diversify their coral collections without purchasing large colonies.
Preserve Rare Corals
Keeping multiple frags of valuable corals can provide insurance against unexpected problems.
If one colony experiences stress or damage, a backup frag may survive and allow the coral to be preserved.
Which Corals Can Be Fragged?
Many popular reef aquarium corals can be successfully fragged.
Some species are considerably easier than others, making them ideal for beginners.
Soft Corals
Soft corals are often among the easiest to propagate.
Examples include:
- Zoanthids
- Mushroom Corals
- Kenya Trees
- Leather Corals
- Xenia
Many soft corals recover quickly after fragging and often grow rapidly.
LPS Corals
Large Polyp Stony (LPS) corals can also be fragged successfully.
Examples include:
- Hammer Corals
- Frogspawn Corals
- Torch Corals
- Candy Cane Corals
- Duncan Corals
Care must be taken to avoid damaging fleshy tissue during the cutting process.
SPS Corals
Small Polyp Stony (SPS) corals are perhaps the most commonly fragged corals in the hobby.
Examples include:
- Acropora
- Montipora
- Birdsnest Corals
- Stylophora
These corals often grow quickly and respond very well to propagation.
Essential Coral Fragging Equipment
Having the right tools makes fragging safer and more successful.
Basic equipment includes:
Coral Cutters
Used for:
- SPS corals
- Branching LPS corals
- Hard skeletons
Quality coral cutters provide clean, precise cuts.
Scalpel or Razor Blade
Useful for:
- Soft corals
- Zoanthids
- Mushroom corals
Sharp blades minimise tissue damage.
Frag Plugs
Small ceramic or aragonite bases that provide a surface for coral attachment.
Frag plugs are commonly used in:
- Frag racks
- Coral grow-out systems
- Retail coral displays
Reef-Safe Glue
Cyanoacrylate gel is widely used for securing coral frags.
It cures quickly underwater and is safe for reef aquariums.
Protective Equipment
Some corals can produce toxins or cause irritation.
Consider using:
- Gloves
- Eye protection
- Good ventilation
Safety should always be a priority.
Preparing to Frag a Coral
Before making any cuts, evaluate the health of the parent colony.
Only frag corals that are:
- Fully expanded
- Showing good colouration
- Free from disease
- Actively growing
Fragging stressed or unhealthy corals can increase the risk of complications.
It’s also wise to prepare all tools and mounting materials beforehand to minimise handling time.
How to Frag Soft Corals
Soft corals are often the easiest place to start.
Step 1: Remove the Coral
If possible, remove the coral from the aquarium.
Step 2: Make a Clean Cut
Using a sharp blade, carefully cut a small section from the colony.
Step 3: Attach to a Plug
Soft corals can be attached using:
- Rubber bands
- Mesh
- Reef-safe glue (depending on species)
Step 4: Allow Healing
Place the frag in moderate flow and monitor recovery.
Most soft corals heal quickly and begin attaching themselves within days or weeks.
How to Frag LPS Corals
LPS corals require a little more care.
Branching LPS
Corals such as hammer and frogspawn corals can often be cut between branches using coral cutters.
Wall-Type LPS
Some species have continuous skeletons and are more difficult to frag safely.
Specialised tools may be required, and beginners should research individual species carefully.
How to Frag SPS Corals
SPS fragging is often straightforward.
Select a Healthy Branch
Choose an actively growing section.
Make a Clean Break
Use coral cutters to remove a small branch.
Mount the Frag
Apply a small amount of reef-safe glue to a frag plug and secure the fragment.
Return to the Aquarium
Place the frag in stable conditions with good flow and appropriate lighting.
Many SPS frags begin encrusting within a few weeks.
Caring for New Frags
The healing period is critical.
Newly fragged corals should be placed in stable conditions with:
- Consistent temperature
- Good water quality
- Adequate flow
- Appropriate lighting
Avoid making significant changes during this period.
Water Parameters for Successful Fragging
Stable water chemistry is essential for healing and growth.
Key parameters include:
Temperature
24–26°C
Salinity
1.025–1.026 SG
Alkalinity
7–11 dKH
Calcium
400–450 ppm
Magnesium
1250–1350 ppm
Nitrate
Low but detectable
Phosphate
Stable and controlled
Consistency is often more important than chasing exact numbers.
The Benefits of Frag Racks
Many reef keepers use dedicated frag racks.
Benefits include:
- Easy observation
- Improved organisation
- Better water flow
- Simplified maintenance
Frag racks are particularly useful when healing multiple corals simultaneously.
Common Fragging Mistakes
Fragging Unhealthy Corals
Always start with healthy, thriving colonies.
Using Dull Tools
Clean cuts heal faster and reduce stress.
Excessive Handling
Minimise air exposure and unnecessary movement.
Poor Water Quality
Fragged corals require stable conditions to recover successfully.
Rushing the Process
Patience is key to successful coral propagation.
Can Fragging Improve Coral Growth?
Surprisingly, yes.
Many coral species respond to fragging by:
- Producing new growth tips
- Branching more aggressively
- Developing fuller colonies
Much like pruning terrestrial plants, controlled fragging can stimulate growth in certain species.
Creating a Coral Garden
As your fragging skills improve, you may choose to create a dedicated coral garden within your reef aquarium.
This allows you to:
- Showcase different varieties
- Experiment with placement
- Grow frags into display colonies
Many stunning reef aquariums began with only a handful of small coral fragments.
Fragging and Sustainability
One of the greatest benefits of coral fragging is its contribution to sustainability.
Aquacultured corals help reduce pressure on wild reefs by:
- Minimising wild collection
- Encouraging captive propagation
- Supporting responsible reef keeping
Today, many of the most sought-after corals in the hobby are produced entirely through fragging and aquaculture.
When Should You Start Fragging?
Many reef keepers begin fragging after their aquarium has matured and corals have established stable growth.
A good rule of thumb is to wait until:
- Corals are thriving
- Water parameters are stable
- You feel confident handling livestock
There’s no rush—successful fragging comes with experience and observation.
Final Thoughts
Coral fragging is one of the most rewarding skills a reef keeper can learn. It allows you to manage coral growth, create new colonies, share specimens with fellow hobbyists, and contribute to the sustainable future of reef keeping. Whether you’re propagating a simple zoanthid colony or creating multiple SPS frags from a prized Acropora, the process offers endless opportunities to learn and grow alongside your reef.
With the right tools, stable water conditions, and a little patience, you’ll soon discover why coral fragging has become such an important and enjoyable part of the modern marine aquarium hobby.
At Charterhouse Aquatics, we stock a wide range of coral propagation tools, frag plugs, reef-safe adhesives, frag racks, water testing equipment, and coral care products to help you successfully grow and share the beauty of your reef aquarium.
