Updated July 2026. The best reef-safe epoxy and glue depends on the job: two-part putty supports and fills gaps, while thick cyanoacrylate gel bonds coral plugs or dry coral bases to rock. Neither product replaces a structurally sound aquascape, and large rockwork should be built securely before livestock is added.
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Use only products whose current label supports aquarium or coral use, and follow the manufacturer’s curing and handling directions. Wear nitrile gloves and eye protection, work with ventilation, keep adhesive off skin and living coral tissue, and store every product away from children and pets. Cyanoacrylate can generate intense heat when it contacts cotton or wool, so keep those materials away from fresh glue.
For coral mounting, dry the plug and contact point when practical, apply the smallest amount that makes a secure bond, then hold it in position until stable. Underwater putty may temporarily affect skimmer behavior or water clarity; monitor the tank and do not leave circulation or aeration off for extended periods.
Plan secure rock placement before gluing by reviewing the saltwater aquarium setup options. If adhesive residue or disturbed debris affects the tank, follow the water-change guide instead of adding more chemicals.
The five established options below cover colored epoxy putty, small and bulk cyanoacrylate gel, and fast-curing two-part coral adhesive.
5. Epoxy
Ah, the infamous epoxy – it can be a bit of a challenge, but fear not! First things first, do yourself a favor and gear up with some gloves. Trust me, it’s sticky stuff!
Here’s how it works – epoxy comes in two parts that chemically react when combined. Just cut off the amount you need and knead the putty together using those trusty gloves. Once the two parts are mixed, the clock starts ticking – you’ve got about 1-2 minutes before it sets!
Now, be warned, epoxy does have a funky smell. So, brace yourself! If you’ve got a protein skimmer running, turn it off before using the epoxy. Otherwise, you might have a bubbly overflow disaster on your hands!
The cool thing about epoxy is that it can cure underwater. That makes it perfect for attaching stony corals to your aquascape!
But here’s the catch – epoxy isn’t like regular glue. It won’t just “stick” things together. Instead, it forms a cement structure around the nooks and crannies, so keep that in mind when working your aquascaping magic.
And the best part? Epoxy is reef-safe, so you can safely use it underwater in your fully established saltwater aquarium. Happy aquascaping! 🌊🧪🔧
4. Small-Tube Cyanoacrylate Gel
These current 20-gram cyanoacrylate gel tubes are easier to control than thin liquid glue and are useful for individual frag-mounting sessions. BRS Extra Thick Gel and PolypLab Premium Coral Frag Glue are separate exact options in this section; choose by bottle format and availability, not by assuming every cyanoacrylate formula is identical.
Dry the plug and coral base when possible, use a modest bead, press the pieces together, and allow the bond to stabilize. Avoid skin and eye contact, keep cotton and wool away from uncured cyanoacrylate, and cap the tube immediately after use. Do not discard a usable tube merely because it was opened once.
3. BRS Extra Thick Super Glue Gel 10 oz Bottle
Super glue is a must-have for every household, and for us reefers, it’s essential to keep several on hand!
I prefer the one from BRS… it’s just a large amount at an affordable price.
Remember, don’t dunk the bottle in your tank (that’s what the single-use tubes are for!). Saltwater will ruin the nozzle and clog it up.
Use the bottle for the first coat before placing the coral in the tank. If you need more, just ask your significant other to bring out the disposable tubes! Easy peasy! 🌊🔧
2. Bob Smith IC-Gel Cyanoacrylate
Bob Smith IC-Gel is a thicker cyanoacrylate gel in a reusable tube. The gel consistency helps bridge small gaps and gives you more control than a runny liquid, but the bond still depends on clean contact surfaces and enough curing time.
Use it above water when practical. If you apply it underwater, expect the outside of the bead to skin over quickly; press and gently twist the plug into place rather than repeatedly adding more glue. Keep the nozzle out of saltwater so the tube remains usable.
1. Tunze Coral Gum Instant
Tunze Coral Gum Instant is a two-part coral adhesive intended for mounting frags and small colonies or supporting modest aquascaping repairs. Mix only the amount you can position within the working time stated on the current package, and knead the components with gloves until the color and texture are uniform.
It can provide a firm mechanical hold, but no adhesive makes an unstable rock structure safe. Support heavy pieces independently, avoid covering living coral tissue, and allow the material to cure according to the manufacturer’s directions before testing the bond.
