The Salty Side: Saltwater Aquariums for Beginners

How to Frag SPS Corals Safely

SPS corals are the architects and builders of coral reefs around the world. In a mixed reef tank, SPS are the corals that consume most of the major and minor elements we provide, growing upwards and outwards, creating the height, providing fish with places to hide. They are also intolerant of each other. If you are growing SPS corals successfully, at some point you will need to start trimming to create more space in your tank, stave off coral warfare, and possibly make some money on the side. In this article, we look at how to frag SPS corals to safely.

how to frag sps corals

What do I need to frag SPS corals?

SPS corals are comprised of branch-like structures that come in a vast variety. Some like the Stylophora grow in a compact structure, others like the Bali Slimer grow broad independent branches, and then you get SPS that grow as plating structures too. Sps corals can be a little challenging to frag. If you look at some the wrong way they can break, while Acropora are hard and brittle. Taking a pair of coral cutters to an SPS can often result in breakages beyond the cutting point.

Superglue Gel – Every reefer should have superglue gel in their reefing cupboard.

Frag Plugs – essential for mounting SPS correctly for frag-rack storage/growing.

Pair of Coral Cutters – A must have item for fragging SPS corals

Inland DB-100 Coral Bandsaw – I cannot say enough good things about this saw. Check out my review here.

Safety Eyewear – You only have one pair. It is worth protecting them.

Gloves – I don’t tend to wear gloves unless I know I will be handling something that can sting me. The choice is yours.

Iodine Coral Dip – you may want to use iodine dip. I use it for LPS, but tend not to use it for SPS.

The assumption is that you will be using protective eyewear whenever you are fragging corals to protect your eyes from damage. The choice to wear gloves is an individuals’ choice.

How to frag Montipora digitata – branching coral

Montipora digitata come in a number of colour variances. The most common of which are the Forest Fire, and Green and Red. The Monti skeletal structure, although fast growing, is prone to breakages by boisterous fish and accidental knocking. When considering fragging Montipora digitata, be prepared for breakages that can happen when you snap the coral cutters closed. 

Once removed from the tank, simply snip the coral branches to size then mount onto a frag plug using a pea-sized amount of superglue gel. Be sure to dry the end of the coral before inserting it into the superglue. Holding the coral and the frag plug together briefly under water will cure the glue.

How to frag Montipora capricornis – plating coral

Plating Monti is another fast grower, given the correct conditions. It can be found in many different colors including red, purple and green. The skeletal structure of the plating coral seems robust to the touch, but it is brittle and you can quite easily snap it between forefinger and thumb. To frag Monti plating coral, it is better to look for a new ‘leaf’ that can be removed in entirety. If you want to break a larger leaf down, be prepared for more to break off than you intended because of the inherent brittleness.

Once removed from the tank, you can use your coral cutters to cut it down further for fragging. Even when using the coral cutters, the plate can break off in unintended angles. I prefer to use my Inland DB-100 Coral Saw to cut it precisely where it want to cut it.

The Monti plating coral can be re-homed without mounting it on a frag plug, but if you want to secure it, dry the underneath of the plate, use a small drop of superglue gel and hold the plate against it under water for a few seconds.

how to frag plating monti

How to frag Stylophora and Pocillopora coral

Both Stylophora and Pocillopora corals are rapid growing, fragile corals. They grow into a compact form that sometimes makes it difficult to separate one branch from another without causing further damage to the colony. So be careful.

Once removed from your tank, you can use the same fragging procedure as you would use with the Montipora digitata.

how to frag stylophora sps

How to frag Acropora sp Coral

Acropora are the slowest growing of the SPS coral group, and also the hardest skeletal structure to cut through. Regular Acropora fraggers tend to remove the entire colony from the tank when fragging to make the process an easier one. However, if you have a large colony that you have never fragged, and cannot be removed, then be prepared. Acropora are very difficult to cut through. The larger the diameter of the branch, the harder it will be. Be prepared for the entire colony to become unseated from the live rock. When you do manage to cut through the branch, the resultant shock can dislodge the entire colony, depending on how securely it is attached.

Once out of the water, you can use the coral cutters to create your frags, but be aware that they will probably not cut the coral at right angles. This makes mounting on frag plugs a little trickier. I prefer to use my DB-100 Coral Saw to cut through the branches neatly. This creates the straight edge I need to mount on a frag plug.

Make sure you dry off the end of the coral before mounting it into a pea-sized amount of superglue gel.

Can I use a Dremel to frag SPS coral?

A Dremel is a hand-held powered tool used in DIY projects. It has a rotating tip that you can attach a number of fittings to, all of which spin. Reefers have tried using the Dremel with a cutting disc, myself included, to power through stoney skeletal structure, and although this can work, it does have its drawbacks.

The constantly rotating blade is thicker than the diamond blade of the DB-100 Coral Saw, and when you begin cutting, coral bits and fragments are liberally catapulted everywhere, including all over your face. What is worse is that the blade gets hot quickly cutting through an Acropora skeleton. This in turn burns the coral and may have an impact on the corals survival rate after fragging. The depth of the rotating cutting disc is quite shallow, so you cannot complete the task in one smooth cut. You will need to cut from the opposite side of the cut too and hope that you can break the fragged bit away. If you have closely growing branches, the rotating disk become too large for the job

In short, I would not recommend using a Dremel.


This article hardly scratches the surface on the many different varieties of SPS, but hopefully those that have been mentioned can be adapted to others. Having fragged every coral, and tried every questionable method, I can safely say that with the correct tools you will have a better quality of fragged corals ready to sell on to other reefers.

My investment in the Inland DB-100 Coral Saw was a turning point for me. I would thorough recommend adding this saw to your tool kit if you want to invest in your own fragging.

For information on fragging soft coral, click here.

For information on fragging LPS coral, click here.

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