Supa glue (cyanoacrylate adhesive) can be used for mounting coral frags in the aquarium. It can form a strong secure bond in a relatively short time frame, and with the right techniques (and lots of practice) can work underwater.
It works best on stony corals and other hard surfaces. With some care it can be used on some soft corals, but is not nearly so effective due to the copious amounts of slime that they organisms generate. Other physical methods of attachment, such as rubber bands, toothpicks, wedging, rubble bowl etc. work better for soft corals, corallimorphs and zoanthids.
The most effective form of the glue is the thicker textured Supa Glue Gel, rather than the thin watery type. The thinner types can be thickened some by placing in the freezer before use.
It must be noted that working with supa glue underwater is not foolproof, and it normally takes a few goes before you can get it to work. You will need to develop your own techniques that work best for you, but here are a few tips:
- if possible, remove one or both of the items to be glued from the tank and dry off with paper towel before applying the glue. Even if you can only do this to one surface, you will at least have a good bond to one side.
- use LOTS of glue. It really doesn't stick all that well underwater or to wet surfaces, and you need to make sure there is plenty to go around.
- after applying the glue, let it start to dry / skin over for a few minutes before trying to place it into the tank.
- when you press it into place, hold it firmly for a few minutes (say 5 minutes). The glue doesn't dry instantaneously. (that's the really boring bit, and can be particularly awkward if you're standing on one leg reaching to the back corner of the rockwork.)
- supa glue can be used in conjunction with epoxy putty combine the adhesive benefits of supa glue with the customisable hard physical shape of epoxy.