Is Super Glue Safe For Aquariums (What you need to know)

Super glue is a great adhesive that is used in many DIY projects. It is strong, fast-acting, and will not drip or run. But is super glue safe for aquariums?

In general, super glue is safe to use in aquariums. Gel glue is better than liquid glue and is best used for aquascaping and repairs to ornaments rather than repairs to aquariums. Superglue won’t create a watertight seal, so you need an aquarium-safe silicone sealant instead.

Is Super Glue Safe For Aquariums

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There are some important things to know before you try using super glue on your fish tank, which I will cover in this article. I will also answer the most common questions about using super glue in an aquarium such as:

  • Can you glue aquarium plants?
  • What is the best glue for aquascaping?
  • Is hot glue aquarium safe?
  • What is the best glue for aquascaping?

This article will answer the above questions and many more so that you can feel more confident when using super glue in your aquarium.

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Is Super Glue Safe For Aquariums
Is Super Glue Safe For Aquariums

Many chemicals should be kept away from aquariums due to the risk of water contamination. Something as simple as aerosols can settle on the surface and contaminate the water, with potentially disastrous effects.

There is no wonder that many people ask, is super glue safe for aquariums. It’s full of potentially harmful chemicals, isn’t it?

From my own experience, copious amounts of research, and talking to other aquarists, I have established that most types of super glue are safe to use in an aquarium. Providing the chemical formula and active ingredients are relatively similar, these glues will react the same.

It is important to check the label for any warnings. Some manufacturers may specifically state that their products are unsafe for use in an aquarium. You also want to look out for added chemicals like mold inhibitors, which are toxic within a fish tank.

I have done some research into the main chemicals found in most super glues.

What Chemicals are in super glue

Super glue contains many chemicals such as cyanoacrylate esters, isobutyl cyanoacrylate, metal powders, and solvents. If you plan to use super glue in your aquarium or fish tank, it is best that the chemicals do not leach into the water.

First of all, there is a chemical called isobutyl-cyanoacrylate. Isobutyl is a skin, eye, and respiratory irritant that is harmful in case of ingestion or exposure to the eyes.

What chemicals are in superglue
There are many chemicals in super glue that are potentially harmful to humans and fish.

Inhalation is also bad for your fish as it can cause respiratory problems such as shortness of breath, coughing, and tightness in the chest. This chemical is not known to be carcinogenic (cancer-causing) or is a reproductive toxin.

There are also cyanoacrylate esters, which are the main ingredients in all super glues and can cause severe skin irritation. This is not carcinogenic, nor is it known to be harmful to your fish, but this chemical could irritate them if they were to come into contact with their eyes.

Many other chemicals are used in super glue that are not necessary to list, but make sure you research the chemical composition of your glue before using it on an aquarium or tank.

Superglue is intended for use with plastics and glass only! Superglue will stick well to these materials because they each have a smooth surface. However, superglue will not bond as strongly to any porous surfaces, including wood, fabric, or ceramic.

Will Super Glue Hurt Fish

So super glue has many chemicals that can be toxic to fish, but only in its raw form. The last thing you want is to have a toxic chemical enter your aquarium and hurt your fish.

It is important to note that these chemicals are not present in super glue when it dries, so the real question is, will superglue hurt fish when dried?

The answer is no! Once the water evaporates from super glue, nothing is left but tiny particles of dried glue strongly bonded together. These will not cause any harm to your fish, but it is still best that the superglue is kept away from them in case they were to ingest it by accident.

It can be difficult to use super glue underwater as it is not designed to be used like this. Contact with water will cause the glue to dry too fast. Contact with water speeds up the bonding and curing process dramatically.

It is preferable if you use the super glue outside of the tank, and once you have carried out the sticking, you can submerge the glued object in some water to make sure it will properly cure.

If you need to do some gluing underwater, I suggest using larger amounts than are necessary, and you should have everything ready to move before you submerge the glue. You will only have a very short time (15-30 seconds) before the glue sets hard, so you will need a steady hand. Once you apply glue to the surface area, apply plenty of pressure and hold still until it sets.

When super glue dries, it will become very hard and will not secrete any harmful chemicals. You will have to break it for the superglue to become liquid again.

If you plan to use super glue for your aquarium repairs, then make sure you use a super glue gel and not the liquid form. A gel super glue appears to be the most aquarium-safe glue.

Is Gorilla Super Glue Aquarium Safe

Gorilla glue is a brand of superglue that is advertised as the “toughest glue on earth.” Their website has many claims that their product is an aquarium-safe super glue and can be used underwater.

Gorilla Glue is mainly made from isobutyl cyanoacrylate like many other super glue brands, and it works in just the same way, so it should also be aquarium-safe.

Many people have been employing gorilla glue to make underwater structures for their fish tanks in recent years. It is typical on several popular forums and websites, and no issues have been reported.

Check further down this article where I have linked to the most popular super glues used in aquariums, including Gorilla Glue.

Is Loctite Super Glue Aquarium Safe

Loctite super glue is another popular brand that is useful for many quick home fixes, but is Loctite super glue safe for aquariums?

Loctite super glue is aquarium safe and used by many aquarists for reef repairs, gluing plant life to rocks or driftwood, and general tank repairs.

I have read many fishkeeping forums where people commonly ask the question “Is Loctite super glue gel aquarium safe?”, and to be honest, both gel and liquid forms of this glue are similar except for its consistency.

Loctite super glue, as with all cyanoacrylate should be safe once cured. Over time, the ingredients can change in any consumer product, but at the time of writing, you should check that the glue contains isobutyl cyanoacrylate.

I prefer to use the gel forms of any super glue brand because it is easier to work with and creates less mess. Liquid super glue can seep into certain materials rendering it pretty useless, whereas a gel will sit in place.

Further down this article, I have left some links to the most popular super glues used in aquariums, including Loctite.

Is Hot Glue Aquarium Safe

Another frequently asked question is whether hot glue is aquarium safe. After doing some research, it’s evident that hot glue is safe for the aquarium. Hot glue comprises a wide range of chemical compounds, but the main component will always be ethyl cyanoacrylate. This is also what superglue consists of, making them both aquarium safe! So yes, hot glue is aquarium safe!

is hot glue aquarium safe
Hot glue is aquarium safe

In addition, hot glue is a very low-viscosity adhesive and, in its raw form, is not harmful to aquatic life. In fact, it is so thin that if some were to drop into the aquarium, they would most likely evaporate before they had any chance of causing harm.

The best advice for any type of glue is to ensure your fish don’t have access to it whilst it is wet, and considering that the glues mentioned above will both dry very quickly, this should not become a problem.

What Super Glue Is Aquarium Safe

I’ve used Gorilla super glue gel on my own aquascaping and haven’t had any issues. Certain glues are specifically labeled as aquarium safe.

Below is a shortlist of both general use super glues and specific aquarium safe super glues:

Seachem Reef Glue (Find On Amazon) is a general aquarium-safe super glue that is especially suitable for fixing corals and other reef structures.

Cyanoacrylate (Find On Amazon) is an aquarium-safe superglue that can be used underwater to fix plants and hardscapes in your tank.

Gorilla Super Glue (Find On Amazon) is another aquarium-safe super glue suitable for both plants and hardscapes.

Loctite (Find On Amazon) is also an aquarium-safe superglue; even though it’s not specifically made for the job, it can be used to fix both live rock and corals in your reef tank. Make sure to use gel not liquid.

Guoelephant Aquarium Glue (Find On Amazon) is excellent for bonding rock, coral and plastics without harming your fish or plants.

You can find the most general super glues at your local hardware store, and you will find specific aquarium-safe glues either online or at your local pet store.

Is Super Glue Good For Sealing Aquariums

Although we have established that many types of super glue are safe to use in an aquarium, they do not give a watertight seal. They are better suited for aquarium repairs rather than making an entire tank watertight.

When super glue dries, it will form microscopic gaps that allow air to escape the tank and water to seep through. This is why you mustn’t use super glue if your aquarium is leaking, as it will only worsen the problem over time by creating more holes in the sealant.

Aquarium Safe Silicone

The best way to deal with a leaky aquarium is always going to be aquarium-safe silicone products, which provide a watertight sealant that is non-toxic to fish and other aquatic life. Using an aquarium safe sealant is perfect for aquarium repairs.

Not only is it a good idea to use an aquarium-safe silicone that is non-toxic, but you should also make sure that your silicone is compatible with glass or acrylic when choosing what kind of glue is best for your particular situation. A general all-purpose non-toxic silicone will work but is not a perfect solution for all aquariums.

Choose a sealant like Marineland Aquarium Safe Sealant (Find On Amazon).

What Super Glue Is Not Good For

Super glue is great for bonding certain surfaces, and it will give a rock-solid hold, but super glue is not good for all surfaces.

It is important to remember that you can’t use superglue on porous materials like rock or sand as it is easily absorbed and will damage your aquatic life over time. It is also not a great choice for fixing holes in the aquarium’s glass, as this is something an aquarium-safe silicone sealant is better suited for.

Super glue is not good for fixing a leak on an aquarium
Super glue is not good for fixing a leak in an aquarium as it is not watertight.

Super glue is also very inflexible when dry, which is why it is not a good idea to use super glue on surfaces that will need to be moved or adjusted at some point. It is best used to stick down objects and then leave them in place.

Below is a list of things that you shouldn’t use super glue for in an aquarium:

  • Repairing leaks.
  • Filling in holes.
  • Making aquarium watertight (it is a temporary sealant).
  • Waterproofing live rock or sand substrates. This is because the super glue will damage your aquatic life when it is absorbed.
  • Fixing cracks or fractures in the glass.
  • Gluing moving parts. This is because super glue is very inflexible once it is dry. It is best used for items that will remain still and not need to be moved after they are glued down, especially because of the strong bond that s formed.

Best Use For Super Glue In Aquariums

The best use of super glue is for aquascaping. Many people use this glue to attach plants and hardscapes to their aquariums. It is also perfect for fixing any broken pieces of glass or acrylic, and it is a great option if your fish are not in any immediate danger from the breakage.

Below is a list of things you can use superglue for:

  • To attach coral fragments to your reef tank.
  • To attach aquarium plants, rocks, Driftwood, and hardscape elements together in the aquarium.
  • To reattach a piece of broken glass or acrylic that is not posing an immediate danger to aquatic life.
  • For smaller aquarium repairs, make sure you have something like silicone on hand for larger leaks.
  • Super Glue is also good for quickly and easily repairing small broken pieces of aquarium equipment, such as pumps or tubing. This quick-fix will not work in the long run but is perfect for emergencies where you need to get your tank back up and running quickly.
  • Super glue is also good for gluing things down like heater wires if they have come loose from their mounts inside the aquarium. This is a better option than using silicone products as it is less likely to clog up the equipment or damage your fish with toxic residue.


I hope this post has been helpful. Please remember that the information provided has been researched by myself based on manufacturer guidelines, information found in other articles, speaking to other aquarists, and my own experiences.

I have researched its use in both marine aquariums and freshwater aquariums. I have looked at common super glue and aquarium super glue.

Obviously, the safest option is to choose aquarium-safe glue, but it may not bond as strongly as the more common super glue.

I cannot be held responsible for any injury or illness caused to yourself, your fish, or your aquarium, so please read my disclaimer before using super glue yourself.

I have used super glue several times myself, and from my own research, I am confident that super glue is safe for aquarium use providing no other chemicals such as mold inhibitors are present, and if you can use the glue outside of the tank, allowing it to dry before returning to the tank, even better.

Many people with reef tanks will use glue to remodel and attach new coral fragments. Even though underwater gluing is not the easiest, it is possible with some persistence. You can also make some pretty neat rock structures by gluing separate rocks together.

When you have finished gluing, always make sure there are no small particles of glue that your fish can swallow and digest, and you should be good to go.

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Jon O'Connell

I have kept both marine and freshwater fish and set up almost 100 aquariums. Although I am no longer doing it professionally, I hope I can help others to enjoy keeping happy, healthy fish by sharing my many years of experience.

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