Can You Use Super Glue in Fish Tank?

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Super glue is a popular adhesive with a short setting time and a laundry list of possible applications. You might have already used it multiple times before. Whenever something breaks unexpectedly, super glue is your friend!

But what about aquariums? Is this miracle glue safe for aquatic life? Will it work underwater? And if so, what can you use it for? Find out the answers to these questions and more in this article! Keep reading to learn all about aquarium DIY-ing with super glue.

Is Super Glue Safe for Aquariums?

If you’ve read super glue warning labels before, you might’ve noticed some worrying side effects listed. When curing, the glue emits minimally-toxic vapors, irritating the eyes and mucous membranes. Sounds pretty bad, right? However, the good news is that super glue is entirely safe for aquariums.

Super glue is made out of synthetic polymers, primarily ethyl cyanoacrylate. Due to its chemical properties, super glue dries almost instantly when exposed to moisture. Using super glue in high-humidity conditions, such as in the aquarium, will speed up the curing time. Cyanoacrylate-based glues aren’t toxic to fish, plants, or live rocks.

Besides, if you’re still worried, you should know that super glue is 100% inert once fully cured. The adhesive won’t give off any fumes or leach anything into the water once the bond becomes fully crystallized. To be extra safe, remember that it takes 24 hours for the adhesive to cure fully. If you don’t want to take any chances, you can move your fish to a different tank while letting the glue work its magic.

Can Super Glue Be Used Underwater?

Unfortunately, this might not be the best idea. Super glue cures with the help of humidity. Moisture triggers a chemical reaction that helps the glue polymerize and solidify. So, we know that water won’t dissolve the glue but will help it work faster. Does that mean you can use super glue straight underwater?

Super glue is widely appreciated (maybe even infamous) for its short drying time. Now, imagine what happens with the glue when it comes into direct contact with lots of moisture, aka water. The glue will solidify instantly. Blink, and you’ll miss the opportunity to bond your materials before it all dries.

At best, you’ll get a weak bond because the glue dried before you could stick the elements together. But what’s more likely to happen is your glue floating to the surface in small, crystalized blobs. Some people recommend choosing gel super glue instead of liquid. That’s because gel dries slower than thinner glue.

I’d recommend bonding your elements first and then introducing them underwater for the best results. For example, take these out of the aquarium if you want to glue plants to rocks. Apply super glue to the parts you want to fix, and gently press the plants onto the rock surface for a few seconds. Once the glue seems stable (it should take 15 seconds at most), you can place your stuff back in the tank.

What is the Best Super Glue for Fish Tanks?

When choosing glue for your fish tank, there are a few things to consider. Most importantly, the adhesive should be cyanoacrylate-based. This ensures the glue is safe for aquatic life and compatible with high-humidity environments. Virtually all super glues on the market fit this criterion, so you got that out of the way.

Then, you’ll have to consider things like viscosity, material compatibility, drying time, bond strength, temperature resistance, and color. From my personal experience, Gorilla super glue will cover all your bases. This brand is a top choice because it has so many pros and no considerable drawbacks:

It has a medium, workable viscosity.

Regular Gorilla super glue is between a runny glue and a gel formula. It works well for a variety of surfaces. It doesn’t run or drip uncontrollably, even on vertical surfaces. You just have to apply a small quantity. You only need one drop per square inch to get a powerful bond.

It’s compatible with most materials.

Whether working with smooth or porous surfaces, Gorilla glue will give you a powerful bond. It works on wood, most plastics, ceramic, rubber, metal, paper, leather, and many more!

It’s also safe for plants, so you don’t have to worry about stem or leaf damage. Just know that this glue is not recommended for polyethylene or polypropylene plastic. Always check out the base materials if you have aquarium decorations made of resin.

It has the quickest setting time you can get.

If you’re working with plants, you can’t keep them out of the water for too long. This is a problem with glues that have a long setting time. Gorilla glue is a good option because it sets after as little as 10 seconds!

Sometimes, it might take up to 45 seconds, depending on how much you use. Either way, you’ll have your plants back in the tank in less than one minute. No need to keep the plants out overnight. Once set, the glue will continue to cure underwater.

It forms tight and highly resistant bonds.

Got speedy fish bumping into things all the time? Gorilla glue is a heavy-duty adhesive. It’s highly effective whether you need to glue heavier materials or just want a resistant bond.

Does fast water movement keep untying some of your plants? Luckily, Gorilla super glue is impact resistant. It can also withstand temperatures between -40°F and 200°F, so don’t worry about your tropical fish aquarium melting away the glue.

It dries clear and creates a subtle look.

Once cured, the super glue is here to stay. This is great if you want a permanent bond. But technicalities aside, you probably also want the result to look good. Nothing worse than having white or yellow splotches of dried glue forever standing out like a sore thumb.

It’s even worse when most aquarium stones and driftwood are dark-colored because this will create an even sharper contrast. One of the best things about Gorilla super glue is that it comes out and dries entirely transparently. You can use it in all colors without any fear.

Where to Use Super Glue in A Fish Tank?

An excellent super glue product is versatile and compatible with many materials and textures. Super glue is also plant and coral safe. This should give you some ideas about your future DIY endeavors. Overall, you can use super glue in many different locations in your tank:

  • To anchor aquarium plants. Use this glue to stick plants on rocks, wood, driftwood, and other decorations. You won’t have to worry about floating plants anymore!
  • To glue coral fragments or live rocks. Want to keep your coral frags well anchored to other structures? Super glue comes to the rescue! Put it on any coral or live rock surface and stick these elements together.
  • To stick rocks together. Are your rock arrangements unstable? You can apply some super glue to create a stronger hold. Use it on various aquarium rocks to build small piles, caves, or swimming passages for your fish.
  • To repair broken decorations. I won’t give you an exhaustive list, but you can put super glue on virtually any surface that needs fixing. Got a cracked plant pot? A broken cave, ship, castle, or statue? Some torn driftwood? These are all easily fixable with a few drops of super glue.

As you can see, super glue is a multi-use tool to help you with all sorts of aquarium décor and repair projects. However, super glue is not the best choice for all applications. There are some surfaces in the tank where super glue use is not ideal.

Where Should You Not Use Super Glue in The Aquarium?

There are two things worth remembering. First, super glue has poor resistance to a mechanical tension. Secondly, super glue has poor adherence to smooth surfaces and chemically-resistant materials. Considering these factors, you should never use super glue to fix aquarium glass, air stones, filters, or certain plastics. Here’s a more in-depth explanation why:

Aquarium Walls

Putting super glue on aquarium glass can go wrong in two ways. First, glass is a very smooth surface, which means the glue won’t form a strong bond. Super glue works best on porous surfaces like wood, stone, ceramic, paper, leather, or rough metal. The bonding power drops significantly when you apply the glue on very smooth surfaces like glass or certain plastics.

Then, aquarium walls are constantly exposed to vibration from different sources. There are water bubblers, filters, and just the general movement of the water itself. As the water moves and puts pressure on the aquarium walls, the glue bond has to stretch and shrink accordingly to withstand the tension.

Super glue can’t do that. This adhesive dries rigid and brittle. Constant exposure to tension will make the bond crack. Don’t expect super glue to fix water leaks in your tank anytime soon!

Aquarium Equipment

Aquarium equipment is also exposed to constant vibration. The filter and the air stone create water movement directly. If your equipment needs fixing, look for a different adhesive, or consider replacing the broken parts! Super glue might not work to repair these components’ cracks or chipped pieces.

The same potential issues apply here— constant mechanical tension will likely break the super glue bond. Besides, aquarium equipment is often made of incompatible materials such as rigid plastics or smooth metal.

Incompatible Materials

Super glue works wonders, and it’s suitable for most surfaces. But it has its limits. It won’t form strong bonds on smooth, non-porous materials or materials with high chemical resistance. This doesn’t pose a threat unless you’re using it to fix essential elements like aquarium walls or equipment.

But, to save yourself the disappointment, remember to avoid using super glue on smooth metals, glass, polyethylene plastic, or polypropylene plastic. If you must use super glue on a smooth surface, you can increase its adherence by roughing the surface with some sandpaper first.

How Long to Let Super Glue Dry Before Putting it in Water?

Super glue takes 24 hours to cure fully. But you don’t have to wait that long. You can introduce it into the aquarium as soon as your bond has set and stabilized. This can take anywhere between 10 seconds to 10 minutes, depending on what formulation and brand of super glue you use. Always read the label instructions.

There are also a few things you can do to help speed up the setting process:

  • Work in a well-ventilated area. Good ventilation helps you avoid unpleasant symptoms from super glue fumes. It also helps the glue set faster. Any method to increase airflow will speed up the drying process, but a fan is probably the handiest.
  • Use warm air. A little-known thing about super glue is that it’s heat-sensitive. Warmer temperatures speed up the chemical polymerization process. This is why you should store your glue in a cold place and away from direct sunlight. You can use a hair dryer to shorten the drying time while the bond sets.
  • Add moisture. Super glue uses water to trigger a chemical reaction while curing. The natural moisture in the air is enough to kickstart the drying process. But you can bump up the humidity even more if you want to speed things up. Spray a very thin layer of water droplets on one of the surfaces you wish to bind together. This should cut the setting time even more.
  • Don’t forget about clamping. If possible, clamp the parts for a few minutes while the glue sets. This creates a tighter, more durable bond and speeds up the drying process. Clamping eliminates movement. Movement decreases surface contact and can result in a weaker seal.
  • Thoroughly clean surfaces before bonding. This won’t necessarily speed up bonding, but it’s still good to do. Super glue adheres best to clean surfaces. If you don’t prep the surfaces first, the dust, debris, grease, or gunk will get in the way of the glue and weaken the bond.

Is Loctite Superglue Safe for Aquariums?

Is Loctite the only super glue you have on hand? No problem! Loctite’s base ingredient is ethyl cyanoacrylate. Any cyanoacrylate-based glue is safe for aquariums. The active ingredients in Loctite super glue become completely inert once cured, which makes the adhesive non-toxic to fish, plants, and corals.

You’d use Loctite just as any other super glue adhesive. If you want to be extra safe, let the glue cure for 24 hours before introducing it into the aquarium. You can also try some of the tips above to speed up the setting process.

Conclusion

Super glue is an aquarium-safe adhesive with lots of useful applications. Once the adhesive cures, it becomes completely inert. Thanks to this, super glue is non-toxic to fish, plants, or corals. You can use it to aquascape and anchor plants, build rock and coral arrangements, and fix broken decorations.

The best part about super glue is that it’s highly resistant to many factors, including shock, temperature, and moisture. It won’t dissolve or leach into the aquarium water. Once the glue crystalizes, it remains stable in virtually all environmental conditions.

Just a word of caution, though. Super glue has poor mechanical resistance. The bond it creates is not elastic. Exposure to constant vibration will break the bond apart. It’s best to avoid using super glue on aquarium glass or equipment like bubblers and filters.

avatar I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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