Best Aquarium Silicone Sealant – Reviews & Guide

If your tank happens to have a crack or a leak, there is no need to go out and buy a whole new tank. This is where a silicone sealant comes in. A silicone sealant is made to seal the crack or spot where it is leaking in order to stop the leakage.

However, you want to make sure you get the right sealant for your needs. Therefore, I have provided a top-ten list of the best silicone sealants for aquariums on the market right now.

Aquarium Silicone Sealant Reviews

Clear Aquarium Silicone Sealant

This silicone sealant is specifically curated for aquariums which is great because you know you will be getting the best outcome for this specific purpose. It forms a strong bond in the aquarium’s surface only in one coat. This is going to prevent further leakages from occurring. Also, it works for both freshwater and saltwater tanks.

When fully curated, it is completely non-toxic for your aquatic life. When used on vertical surfaces, it will not drip down so you will get the best curation on the cracked glass. Also, it can be applied to temperatures ranging from 0 degrees Fahrenheit to 120 degrees Fahrenheit.

Something to note about this sealant is that it is highly sticky and will leave a residue on your hands, so it is probably best to wear gloves while applying this. Also, it has a bad odor that smells kind of like vinegar.


  • Non-toxic to aquatic life once fully curated
  • Will not drip on vertical surfaces
  • Works for both freshwater and saltwater tanks


  • Very sticky so gloves are a good option
  • Bad odor that smells like vinegar

Aqueon Silicone Sealant

This silicone sealant creates a well-bonded high-quality seal that will not crack or shrink. This means that you most likely will not have to reapply it after you apply it once. It is easy to use to stop leaks from occurring in your aquarium. Also, it is completely safe and non-toxic.

It comes in both clear and black colors which is perfect because most aquariums are either frameless or they have a black rim. If you have a crack in your aquarium, the clear color will not impact the appearance at all. If you need to put it on the frame of your aquarium, you can use the black color if your frame is black for the same effect.

One bad thing about this product is that the packaging and the lid is slightly low-quality, so it might leak out of the bottle over time and create a sticky residue.


  • Safe and non-toxic to use
  • Comes in clear and black
  • Will not crack or shrink over time


  • Low-quality packaging
  • Will leave sticky residue on the bottle

Aquascape Black Silicone Sealant

This silicone sealant works specifically for something you need covering up with something black. For example, the black trimming on your aquarium. This probably would not work for the glass on your aquarium because of its color. It is completely safe for your aquatic life, aquarium, and plants.

It creates a strong, waterproof bond that over time will not shrink or crack. Therefore, you will not need to reapply it after you apply it first. The excellent adhesive properties of this sealant ensures that it is long-lasting and reliable.

Something to note is that the odor and fumes coming from this sealant is very strong and might affect your eyes. Therefore, goggles might be a suitable option if you decide to go with this sealant.


  • The black color is great for black trimming or other surfaces
  • Long-lasting and reliable
  • Completely safe for aquatic life and waterproof


  • Because it is black, it is not suitable for aquarium glass
  • Extremely strong odor

Loctite Clear Silicone Waterproof Sealant

This silicone sealant works perfectly to make a waterproof bond that prevents any cracks or leakages in your aquarium. This option is great if you are looking for a sealant that is multipurpose. You can use this sealant for so many things other than your aquarium including doorways, glass, tile, etc.

It is made from clear silicone so you wouldn’t be able to tell it is there on an aquarium’s surface. This is great because it does not affect the overall look of your aquarium. In fact, it doesn’t even look like you applied a sealant in the first place.

Something to note about this silicone sealant is that the packaging is made from slightly low-quality materials. Sometimes the ending of the tube breaks open for the sealant to ooze through.


  • Clear silicone won’t make it visible on surfaces
  • Multipurpose
  • Waterproof


  • Packaging is low-quality
  • Bottom of the tube tends to break open

Dap 00688 All-Purpose Adhesive Sealant

This silicone sealant is made from 100% silicone and it is safe and easy to use. It is very long-lasting and won’t crack or shrink over time. This is great because you won’t have to reapply it over time. You just apply it once and you are good to go. It is non-toxic and waterproof, so it will not harm your aquatic life or plants. Also, it is applicable for both saltwater and freshwater tanks.

Once applied, it takes only 24 hours to cure completely. This a short time compared to other sealants, so you’ll be able to return to your normal tank in no time.

Like some of the other sealants, the packaging is slightly low-quality. Therefore, you will have to be careful with how you are handling it. The top tends to pop out, and you risk the bottom opening as well.


  • Only takes 24 hours to cure
  • Applicable for both freshwater and saltwater
  • Long-lasting and won’t crack or shrink over time


  • Bad odor
  • Packaging is low-quality

MOMENTIVE RTV108-300ML RTV 108 Silicone

This silicone sealant works for sealing gaps up to ¼ inch. This is perfect for cracks in aquariums to stop leakages from occurring. Also, it is multipurpose, so you can use it for other surfaces in your home that may need repairing. It is completely waterproof, so the water in your tank will not affect the bond of the sealant.

If placed on a vertical surface, it will not drip or move down the tank. This is due to the extremely strong texture of the paste. This also explains how strong the bond it will be, so there will be no leakages once this sealant is applied. It is long-lasting and resilient against your tank.

One thing to note about this sealant is that it takes a while to cure, so you may need to find another home for your aquatic life for a few days. This isn’t too big of a deal but can be a hassle.


  • Will not drip on a vertical surface
  • The paste is very thick and strong
  • Long-lasting and resilient


  • Bad odor
  • Takes a few days to completely cure

GE 1200 Series Construction Silicone Sealant

This is a high-strength silicone sealant made from 100% silicone. Also, it is completely waterproof, so the water in your tank will not affect the bond of the sealant. You can use it on a variety of surfaces no matter the temperature which is great if your aquarium is heated.

It is completely clear in color which will not affect the overall look of your tank. Most likely, no one will even be able to tell a sealant was applied. There are no toxic ingredients in this sealant, so your aquatic life will not be harmed by using this. Also, since it is waterproof, it can be used on both the interior and exterior of your tank.

Something to note about this sealant is that it works much better on glass tanks than acrylic tanks. I would not choose this specific sealant if your tank is made from acrylic material. Also, it is a very thick paste, so it will be hard to squeeze out of the tube.


  • Completely clear in color
  • Completely waterproof so it can be used on both the interior and exterior of the tank
  • No toxic ingredients


  • Hard to squeeze out of the tube
  • Doesn’t work the best for acrylic tanks

Smooth-On Sil-poxy Rubber Silicone Adhesive

Thie silicone sealant does an effective job of providing a strong bond that is long-lasting and reliable. It is completely waterproof, so you can apply it to either the interior or exterior of your aquarium without worrying about the water weakening the bond. Also, it is multipurpose as it works on ceramic, tile, metals, and more (along with aquariums).

Something to note about this product is that it comes in a very small tube, so you will probably have to replace it if you use it all at one time. However, a little goes a long way, so you might get away with multiple uses out of it.

You have to wait a while for it to completely cure, but once it is finished, it doesn’t budge and you are good to go.


  • A little goes a long way
  • Completely waterproof
  • Long-lasting and reliable


  • Takes a while to cure
  • Comes in a very small tube

MarineLand Silicone Squeeze Tube

This silicone sealant is great because it is specifically made for aquarium usage. Even if it isn’t multipurpose, it only means that it is specifically tailored to the needs of an aquarium and therefore will provide a stronger bond.

It is completely clear so you will not be able to even see it on a clear aquarium. This means it won’t affect the overall look of the aquarium which is a priority for most.

Something to note about this product is that you must make sure that the area is dry before using it otherwise the sealant will not bond to the aquarium. However, it only takes about a day to cure which means less hassle on you. Also, like a lot of the other sealants, the tube is very poorly packaged.


  • Specifically made for aquarium usage
  • Completely clear so you won’t see it
  • Only takes about a day to cure


  • Tube is poorly packaged
  • Must make sure the area is completely dry before applying it

Gorilla 100 Percent Silicone Sealant Caulk

This is a versatile multipurpose silicone sealant that can be used for other projects other than aquarium usage. However, it is still optimal for your aquarium. It provides a strong, long-lasting bond that you will not need to reapply.

It is completely clear in color which will not affect the overall look of your aquarium which is optimal. Most likely, people will not even notice a sealant was applied. At first you might be able to see it, but it dries completely translucent.

Something to note about this sealant is that it comes in an extremely small tube, so it may need to be replaced if you use it all in one project. However, it is also important to know that a little goes a long way with a sealant like this.


  • Long-lasting
  • Dries completely clear
  • Multipurpose


  • Comes in a small tube
  • Bad odor

Features of a Good Aquarium Silicone Sealant

If you are looking for an aquarium silicone sealant, it is essential that you first understand all of the different factors that will impact which one you choose. This will ensure that you purchase the best one that meets all of your wants and needs.

  • Waterproof: Aquarium silicone sealants are completely waterproof. This means that it can be applied to both the exterior and interior of the tank. The water will not affect the strength of the sealant once it is completely cured.
  • Heat resistant: Aquarium silicone sealant is also heat resistant. This means that if you have an aquarium heater or UV sterilizer, the sealant will not be affected by the heat. It will not sag, crack, shrink, or drip because of heat.
  • Thick consistency: Good aquarium silicone sealants always have a thick consistency to make it stay in place. This will prevent any dripping from occurring on a vertical surface.
  • Long-lasting: A good aquarium silicone sealant will be durable long-lasting. This means that over time, you will not need to reapply the sealant. Once completely cured, it should stay in place permanently.
  • Safe: Aquarium silicone sealants must be safe for the aquatic life in the tank. You have to be careful when buying a sealant, as some are not branded specifically for aquarium usage. Buying one that is specifically tailored to use on aquariums is your best option so you can be sure it is safe for your aquatic life.
  • Clear color: Most aquarium silicone sealants come in clear color. This is great for aquarium usage since most repairs will be done on the surface of the tank. Therefore, the sealant will not visually impair the looks of the tank. In fact, most people won’t even notice the sealant was applied.

How to Use Aquarium Silicone Sealant

Most aquarium silicone sealants are applied pretty much the same way, but every product is going to have its own instructions. It is important that you read those before doing anything.

  • It is crucial that you empty everything out of the tank before applying the sealant. This is due to the sealant emitting toxic fumes before it is completely cured. Do not put anything back in the tank until the sealant is cured in order to prevent anything in your tank from being contaminated.
  • Before applying the sealant, the surface must be completely dry. This will ensure that the sealant stays in that one area only.
  • The next step is applying the sealant. Keeping a steady hand is key. Only apply the sealant where it is absolutely necessary to avoid using too much. It is important that you apply a generous amount of sealant to the surface without it being too much.
  • Finally, let the silicone sealant cure for the amount of time stated for the specific product you are using. Different sealants have different times that it needs to cure. It is crucial that you do not start using the tank again until it is completely done curing. Let it sit for at least the amount of time it says. If it does not look completely cured, let it sit for another day or so.

Purpose for Aquarium Silicone Sealant

Aquarium silicone sealant is meant for concealing cracks that may have happened on the surface of your aquarium. It creates a strong seal that will prevent any leakages or further cracks from happening. Silicone sealants are resistant to heat, so the heater in your aquarium will not impair the strength of the sealant.

Good aquarium silicone sealants will not shrink or crack. It also has a thick enough consistency to not drip or move along a vertical surface. Also, aquarium silicone sealants are completely safe for the aquatic life once it is completely cured. It usually cures in 24 to 48 hours.

Aquarium silicone sealants are good to use for both freshwater and saltwater tanks. They can help repair the aquarium glass or acrylic material, any rocks or decorations, and other aquarium features. They also will work on other surfaces beside aquariums.

A silicone sealant is what already holds the aquarium panels together, so it completely safe for the material of the tank. Silicone sealants are the most effective way of repairing any small damages to your aquarium. Silicone sealant repairs can often last a lifetime if done properly.

FAQ’s for Aquarium Silicone Sealant

How do I remove the aquarium silicone sealant?

There are a few ways to remove aquarium silicone sealants from different surfaces. One way is to use a razor blade to carefully scrape the sealant off. If it is a large amount of sealant, it can easier to scrape it off if you release the bond first. This can be done with a heat gun or blow dryer. It is important to wear protective gloves when removing sealant to ensure your own personal safety.

Can I use it on my aquarium rocks?

Yes. Aquarium silicone sealant is one of the best things to use when sticking rocks together. Creating an underwater landscape with attaching different aquarium rocks together is a great way to give your aquarium a visual appeal.

Is it easy to use?

Yes. Aquarium silicone sealant is extremely easy to use. It is important to follow the instructions used on the specific product to avoid making any mistakes.

Are there toxic fumes?

When first applied, there are some odorous fumes with most sealants. However, it is not dangerous for human use. Using a mask is recommended for people sensitive to different odors. After the sealant is completely cured, there will not be any fumes.

How long will the sealant last?

Good aquarium silicone sealants are very durable and long-lasting. If used properly, it should never need to be reapplied and will last a lifetime. If it does happen to have any cracking or shrinking over time, it should only need to be reapplied once.

If your aquarium seems to have a scratch or crack, applying a silicone sealant is the best option to avoid any leakages from occurring. However, sometimes it can be difficult to find the best sealant that works for your needs and aligns with your priorities. Hopefully this list brought you clarity as to which silicone sealants are the best and highest quality.

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