A quick review of cyanoacrylate coral fragging glue and two-part epoxies

Ready to get started with fragging your first corals but aren’t sure which cyanoacrylate coral fragging glue you should buy? Here is a quick product review of commercially available glues for use in coral fragging. Most of the coral adhesives in the market fall under one of two categories:

  • Cyanoacrylate adhesives
  • Two-part epoxies

Cyanoacrylate gel is a great all-around adhesive. It is non-toxic, cures in the air or underwater and really makes a strong bond. It is my adhesive of choice for most coral fragging.  Two-part epoxy, on the other hand, is great for when you are trying to attach two relatively larger pieces of rock together. There is no shortage of products available to meet all of your cyanoacrylate adhesive and two-part epoxy needs. Let me show you some of the more popular products and their differentiating features.

Cyanoacrylate coral fragging adhesives

Reef Glue

reef glue cyanoacrylate gel

Reef Glue is listed as a fast-acting cyanoacrylate adhesive. The marketing pitch (I’m a marketer at heart, so I say that affectionately) is that their glue is 17x’s thicker–but 17 times thicker than what? My guess is thicker than regular cyanoacrylate…NOT other cyanoacrylate gels. But still, the marketing message is compelling, because, as we all know, thickness matters when it comes to fragging…seriously. Runny cyanoacrylate gel makes a mess and will probably end up causing you to stick your fingers together. The price point is relatively modest. At the time of this article, the product is between $8-9 with free shipping on Amazon for the 20g size.

According to the manufacturer, Reef Glue is a superior cyanoacrylate (superior to what?) that bonds within seconds (is this different than any other cyanoacrylate?) and can even be used underwater (that’s an important application). The product is packaged in an aluminum tube for extended stability beyond products in plastic bottles. Now we’re getting somewhere.


coraffix cyanoacrylate gel

CorAffix is a product sold by Two Little Fishies, the company famously headed by Julian Sprung, author, scientist and apparently cyanoacrylate adhesive mogul. CorAffix is a premium-priced cyanoacrylate adhesive (I noticed that neither company calls their product a glue…I wonder why that is?). The list price on Amazon is $21, but at the time of this article, it is discounted down to between $12-13, also available with free shipping.

CorAffix is an ethyl cyanoacrylate bonding compound with a viscosity similar to honey…and WHO, may I ask YOU, doesn’t like HONEY? Interestingly, this product is listed for attaching stony corals (and other sessile invertebrates) in natural positions on the live rock in aquariums…which I guess means that if you choose to mount your corals in an unnatural position, your off-label use may end up voiding the warranty…if there is a warranty…but I digress.

The manufacturer instructions actually suggest you use this product along with AquaStik to attach larger coral heads.


coral glue cyanoacrylate glue

Echo tech markets a cyanoacrylate gel branded CoralGlue. Their smart, yet simple packaging carries the abbreviation Cg, which makes their CoralGlue product look like it belongs on the periodic table of elements. The geek in me loves this little bit of branding. On Amazon, this product page boasts the braggariffic claim, “…a coral glue that actually works!” The product has a replaceable pin cap and has a shelf-life of over two years if kept in the refrigerator. According to the manufacturer’s website, this product sets underwater in less than 10 seconds, cures in 5 minutes and is made with triply distilled purity.


Two-part epoxy coral fragging adhesives


aquatic two-part epoxyAquaStik, also sold by Two Little Fishies, is a two-part epoxy. It’s a non-toxic putty that comes in two strips–when you mix the two parts together with your hands (as directed by the instructions), the epoxy heats up, due to a chemical reaction and becomes sticky. Two-part epoxy is a preferred adhesive when you are trying to stick a big rock onto another rock. In my experience, cyanoacrylate is superior from the perspective of the strength of the bond, but it can be difficult to get sufficient contact between the two surfaces when using cyanoacrylate on larger rocks. The much thicker putty (I wonder how many times thicker?) is easier to use from that perspective. You can get stone grey or a ‘designer’ color that is supposed to emulate the look of coralline algae.



holdfast two part epoxy

Instant Ocean sells a two-part epoxy product under the trade name HoldFast. As far as I can tell, this is essentially the same product as AquaStik, although the color is essentially green. If you can live with that and don’t want a specific color, pick up whichever product is available and/or cheaper.

Fluval Sea

fluval sea epoxy

Fluval also sells an epoxy stick under the name FluvalSea Aquatic Epoxy Stick. This epoxy cures in 24 hours underwater or 48 hours outside of the water. It is non-toxic (as are all of the epoxies) and is safe to use in freshwater or saltwater tanks.




Using an epoxy and cyanoacrylate gel together

The CorAffix product page on the Two Little Fishies website provides instructions on how to use their two-part epoxy and the cyanoacrylate gel together. The short version of this is that you press the stony coral into the epoxy to make an indentation that is exactly the same size and shape as the frag, give the epoxy a few minutes to cure and then coat the frag with the cyanoacrylate to hold it into place. I had not seen that previously, it seems to make a lot of sense. While expensive to use two $10 products to mount the corals, it does sound like a superior system to just gluing, which sometimes does result in a few problems.


My firm belief is that cyanoacrylate and epoxy are commodity products–the chemicals are what they are. The differences between the products are in the packaging and the marketing messages they use to try and influence and differentiate. Like a lot of things in this hobby, picking the best product is going to be more about picking your favorite than picking the superior product. How about you, do you have a favorite?

For more information

To learn how to frag corals, buy the book, How to Frag Corals

how to frag corals

To learn more about other equipment and aquarium products, check out the

Equipment Page

Resources Page

For more information about adhesives and epoxy, I encourage you to check out the following links:






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