Adhesives for the Aquarium

There are many different types of adhesives that you would use in aquarium. The most important consideration is that they are aquarium safe or non-toxic to the corals and fish in your tank.

Attaching a coral onto the rock in your aquarium with "Tootsie Roll" epoxy

If you have purchased a coral fragment that is already mounted on a rock (like our farm does) , you can mount that rock to your live rock, already under water, in your aquarium. Probably the most commonly used adhesive is a solid two-part coral epoxy that looks like a Tootsie Roll.

If you ordered one of our beginner packages, you should have received a free epoxy tootsie roll (pictured left) with the package. It is about the size and shape of a Tootsie Roll and has an outer coating that is typically green and an inner coating a slightly different color, often white. This epoxy is only safe to use underwater in aquariums when it says so on the container or sold by a reputable coral farm. Some of these are not safe so be sure to buy one that has been tested by others. The one we use has been used thousands of times with no adverse effects reported.

The way you use this epoxy is to cut off a small piece. Typically start with the the size of a marble. U can remove the outer protective plastic coating, which keeps it from drying out and then you mix it together by hand. By mixing it, that starts the chemical reaction. You want to make sure that you mix colors thoroughly by pulling on it, and by pushing on it, and by squeezing it so that before you actually use it, there is one continuous color throughout the epoxy.

If you have an area that's not properly mixed, where the resin is not mixed with the hardener, then it will never set up and get hard and you just have to scape it back off and start again.

Common Uses

The most common use for coral epoxy is for attaching the coral frag to parts to one of the live rocks already in your tank. The way to do this is to select the coral frag, which should already be mounted on a small artificial rock and turn it over. (And it is safe to have the coral out of the water for period of time. It won't hurt it.) Hold it in your left hand and take the mixed up epoxy and push it onto the bottom of the rock.

You just want to say smash it into half of the circle and then take your finger and feather the edges out along the edge of the rock so that it increases the adhesion of the epoxy to the rock. And then you can turn it over, put it in the aquarium and hopefully you've selected a site already and you cleaned the site off of any algae and any loose debris. Push the rock with the epoxy down onto your live rock in the aquarium and push it down against rock, and then twist it slightly.

The idea is you want to get as much surface adhesion is possible. You push it all the way down to where the rocks touch each other to push it down to where the epoxy is just squeezing out. And then when you think that you have good at the connection between the two, you can take your finger around the outside and then feather this both up on the rock and down on the live rock in the aquarium.

Now in the aquarium you can have the epoxy showing and won't be terribly attractive at first, but very quickly in a healthy aquarium it will become covered with the various algae and other growths, so that in a short period of time, you'll notice that the epoxy is blended into the rocks colors. The trick on two-part epoxy is to support it while it sets up. It typically takes maybe 30 minutes to an hour to set up and you certainly don't want anything bumping it so you can cover it or support it temporarily while it hardens. And then once it is set up, you can remove whatever to protecting it

Attaching glass to glass

There are other adhesives that you use on your aquarium before it is filled with water. One of these is called the silicon caulk. Typically this is used to seal cracks in the glass. It is needs contain 100% silicon caulk, and nothing else. The thing you want to watch out for here is make sure to aquarium safe because some silicate silicon caulk has a anti-fungal agent put into it, so that when you caulk your outside door or window, mold wont grow on it. This additive is toxic, so don't use caulk that contains it. We have used a product by General Electric, called GE 012 in the past successfully, but arent going to warrant that it is safe. Try it at your own risk, but we havent had any problems with it.

Silicon caulk is very useful for either making any a glass aquarium from scratch or even repairing a glass aquarium. It is quite easy to work with, and you can trim it with a razor knife and and then once it cures, silicone caulk is inert and will not harm inhabitants in the aquarium. Don't put underwater until it's completely set up and cured. And certainly, you don't want to put any pressure on it until its's cured either, such as filling up the aquarium, because caulk only has limited ability to withstand a load stress

Adhesives for Acrylic Tanks

If you're using an acrylic tank, you can only use one of the organic solvents such as methylene chloride. rather than selecting a caulk because the organic solvents will actually fuse the two sheets of acrylic together. But this is best left for experts, as it can be very toxic to breath or even if it gets on your skin. For more information on this see a acrylic tanks.