Top Aquarium-Safe Silicones: Ensuring the Health of Your Fish

Estimated read time 20 min read

From aquarium substrate and decorative rocks, all the way to filter systems, water heaters, and air pumps, setting up an aquarium requires several essential elements to work together. One of the most important parts of an aquarium, and I think you would agree, is the silicone sealant.

We decided to take a closer look at some aquarium safe silicone available to find the top brands out there. Of the many brands we’ve seen, these are the best aquarium safe silicone brands to buy in 2021:

Aquarium safe silicone is a real lifesaver when it comes to fixing minor or major leak issues. Silicone sealant provides a quick solution to save your aquarium inhabitants, whether fish or plants, from injuries and stress. It’s also pretty handy to use as an adhesive if you want to attach something to the glass of the aquarium.

The number one thing about aquarium safe silicone, besides being non-toxic to your aquarium inhabitants, is that it lasts for years upon years once cured.

Today, we’re taking a closer look at aquarium safe silicone to provide you with all the information you need before making a purchase. We’re also including a list of the six aquarium safe silicones to help you land an awesome deal. Let’s dive in!

Further Reading: See More Of My Recommended Tools To Clean A Fish Tank.

Six Leading Aquarium Sealants for a Healthy Aquatic Environment

Understanding Aquarium-Safe Silicone: Composition and Functionality

First things first, you should understand what aquarium silicone actually is and how exactly it works.

As you can probably tell, aquarium silicone is a type of sealant that’s primarily made of silicone. Consequently, it’s known to offer a tough and reliable performance when it comes to adhesion jobs. This is why silicone sealants can be used in a wide range of applications, not just for aquarium maintenance purposes.

Silicone sealants can endure extreme temperatures and resist ultraviolet rays. They also come with excellent movement attributes and high versatility, making them the top choice for aquariums.

But it doesn’t stop there! What makes silicone sealants particularly useful in aquarium situations is that silicone is one of the very few adhesive materials that actually clings to glass – which makes up most of any aquarium.

So how does aquarium silicone work? This sealant holds together your fish tank by securely binding glass parts. This includes fastening any damaged areas or leaky spots in your aquarium.

You should know, however, that silicone doesn’t bond immediately after application like super glue. Instead, it goes through a process called curing where it usually takes about one week for silicone to completely cure as it slowly dries.

You can recognize if your silicone sealant is still curing by being wet to the touch and smelling like salt and vinegar chips.

It’s important to note that silicone doesn’t cure underwater, so if you apply it with water inside the tank, it won’t dry out. Silicone sealants should be air-dried until they’re completely cured to be deemed aquarium safe.

Here is a great video by Joey about Aquarium Safe Silicone

Comparing Aquarium-Specific Silicone to Regular Varieties

Now, you’re probably wondering about the difference between regular silicone and aquarium safe silicone. Why can’t you just use them interchangeably?

While both products offer similar performance in creating strong bonds for sealing and repairing leaks, cracks, or other damages, regular silicone is meant to tackle an array of applications in building and household projects.

As for aquarium safe silicone, it’s designed in a specific manner to be non-toxic to fish and aquatic plants, keeping them safe and healthy even after curing.

Generally speaking, you want to look for a sealant that contains 100% silicone. Read the label carefully because some manufacturers will claim 100% silicone content but they actually use other additives that are usually stated in the fine print. Don’t worry too much though, reputable brands like the ones we’re listing today are true to their label claims.

That being said, if you notice the terms Mold-Free, Mildew-Resistant, Anti-Microbial, or Bacteria Protection on your tube of silicone, do not use it in your aquarium. Such products contain fungicides and bactericides that may end up killing your fish and aquatic plants.

The Importance of Choosing Aquarium-Specific Silicone

Aquarium safe silicone is an excellent solution to fix minor leak issues or attach objects to the glass of your fish tank. But what makes it better than other sealant types on the market?

Well, here are some benefits that accompany using aquarium silicone:

  • It’s non-toxic to fish and aquatic plants.
  • It contains authentic silicone so they’re safe to apply in any glass aquarium.
  • It’s transparent so it won’t interfere with the overall appearance of your aquarium.
  • Once cured, the silicone seal isn’t at all affected by the constant submersion in water.
  • It works great for both freshwater and saltwater tanks.
  • It resists cracking, shrinking, sagging, or drooping.
  • It’s easy to apply and forms very strong bonds.
  • It resists ultraviolet radiation, ozone, and airborne chemicals.

Then, are aquarium safe silicones simply perfect? They’re extremely handy, no doubt about it, but there are a couple of drawbacks involved with such seals.

For one, silicone sealants don’t cure when wet. They take around 7 days to completely cure, and they’re not quite suitable for acyclic tanks.

Step-by-Step Guide to Applying Silicone in Your Aquarium

Although there might be slight variations among the different brands of aquarium safe silicone, the application process is generally the same. Here’s a step by step guide for using aquarium silicone:

  • Drain your fish tank and make sure it’s totally empty.
  • If there’s any old silicone where you want to apply the new seal, use a razor blade to get rid of all old silicone. (More on the removal process later)
  • Prepare the area to be sealed by cleaning it up and smoothing it out with sandpaper. This roughens the surface a bit to ensure a stronger hold.
  • Make sure all the surfaces are completely dry. As we mentioned above, the silicone sealant doesn’t dry when wet.
  • Gently apply silicone beads at the site of the leak or along the tank’s edges. Here, you can use a caulking gun or the applicator that comes with the tube.
  • Use fortified duct tape to make sure all corners are tightened. If you own an aquarium sized more than 75 gallons, then wooden clamps are a better option to hold everything in place while the sealant cures.
  • Using your finger, smooth the silicone along the seams to remove excess product and create a sleek surface.
  • After that, you just need to wait until the curing process is finished. In general, it takes about 1 to 2 days for aquarium silicone to dry, but it can take up to a whole week for it to completely cure.

Click here to learn how to reseal your aquarium using an aquarium sealant.

Aquarium leaks can be a nightmare for any fish enthusiast. Don’t let a leaky tank ruin your day! Learn how to reseal your fish tank with our comprehensive guide. Click here to discover the steps and tools you need to fix your aquarium and prevent future leaks.

Effective Techniques for Removing Old Silicone from Aquariums

When it comes to removing aquarium silicone sealant, there are a couple of methods you can use depending on how much silicone you want to get rid of.

If you’re dealing with a smaller seam or area, you can simply use a razor blade to scrape off the silicone. This is a pretty easy and quick way to get any sealant off the surface, but it doesn’t work all that well if you need to remove a lot of silicone. Not only will it leave many tiny bits of sealant behind, but it’ll also cost you much time and effort.

If you want to remove aquarium silicone from a large area or from the corner seam, you should start off by using a heat gun or a hairdryer to blow hot air onto the silicone seal. Note that a hairdryer will take a lot more time to provide the same effect as a heat gun because it doesn’t get as hot, however, it’ll eventually get the job done.

Once the silicone is warmed up enough to become more flexible, use a razor blade to scrape it off. Remember, you don’t want to melt the silicone, just get it softer so it’s easier to remove. After you’re done, go in with a textured sponge and scrub away anything left behind.

Trusted Silicone Brands for Aquarium Safety and Durability

Below you’ll find a list of six aquarium-safe silicones that you can use in your tank the next time you spring a leak.

1. ASI Clear: The Optimal Choice for Aquarium Sealing

Clear Aquarium Silicone Sealant - 10.2 Fluid oz Cartridge
Get ASI Clear Aquarium Silicone Sealant

Specifically designed for aquariums, this Clear Aquarium Silicone Sealant from ASI offers excellent tensile strength and tear resistance. It doesn’t require the use of primers to form solid cohesive bonds with glass, which means you don’t have to worry about prepping.

Once it completely cures, the produced tight seal remains unaffected by continuous immersion in both freshwater or saltwater tanks. It’s so good that it withstands constant stress on aquariums up to 750 gallons, operating from -70°F to 450°F (-57°C to 233°C).


  • Remains intact under immense stress
  • Withstands extreme temperatures
  • Doesn’t need primers


  • Dries too fast for some users

2. Aqueon Sealant: Reliable and Safe for Aquatic Life

Aqueon Silicone Aquarium Sealant (10.3 oz)
Get Aqueon Silicone Sealant

Highly effective and reliable, the Aqueon Silicone Sealant is one of the top-rated aquarium sealants with hundreds of positive reviews to back it up.

Made out of 100% non-toxic silicone, the Aqueon Silicone Sealant is safe for all fish and any aquarium. It creates a strong, waterproof seal that won’t shrink or crack. It’s also permanently flexible with a super-easy application that dries out very fast for quick solving of leaks.

This long-lasting aquarium safe silicone won’t leave behind any traces or stains, so your tank will look as good as new without any damaged appearance.


  • Very easy to apply
  • Permanently flexible
  • Dries fast


  • On the pricey side

3. Loctite: Versatile and Waterproof Protection

Loctite Clear Silicone Waterproof Sealant 2.7-Ounce Tube (908570)
Get Loctite Clear Silicone Waterproof Sealant

When it comes to accurate sealing, the Loctite Clear Silicone Waterproof Sealant is a great product for the job. Not only is it formulated to never peel, crack, or shrink, but it’s also suitable for use with either freshwater or saltwater aquariums.

The Loctite Silicone Sealer is quite versatile, bonding a wide array of materials including glass, ABS, wood, porcelain, ceramic, fiberglass, and stainless steel. It’s made out of clear, authentic silicone, so it’s guaranteed to not harm your aquarium inhabitants.


  • Binds a wide variety of materials
  • Handy size
  • Affordable


  • Packaging bursts easily

4. ASI Black: Aesthetic and Functional Sealing

Black Aquarium Silicone Sealant - 10.2 Fluid oz Cartridge
Get Black Aquarium Silicone

Not everyone wants a clear sealant to fix a leak or patch a pond liner, sometimes a black aquarium safe silicone is needed. If you’re on the same page, then you’re going to love the Aquascape Black Silicone Sealant.

This non-toxic silicone sealant creates a durable, watertight bond that’s not compromised by continuous exposure to water. Thanks to its black color, this sealant will give you an invisible repair that works beautifully with ponds, aquariums, and terrariums.

You should expect, however, a particularly strong smell upon applying this sealant, so be sure you do it in a well-vented space.


  • Creates an unnoticeable black seal
  • Works great for aquariums and ponds
  • Very durable


  • Smells a bit too strong

5. Dap 00688: Multipurpose and Aquarium-Safe

Dap 00688 All-Purpose Adhesive Sealant, 100% Silicone, 2.8-Ounce Tube
Get Dap All-Purpose Adhesive Sealant

Is DAP 100% silicone safe for fish tanks?

This reliable all-purpose sealant is certified as aquarium safe. It’s odorless, dries clear, and stays flexible after application.

The Dap 00688 All-Purpose Adhesive Sealant is very easy to use, allowing you to simply scrape it off or cut it even if you accidentally squeezed out too much or put it over the wrong area. This makes it a good choice for the not-so-handy aquarists.

This 100% silicone sealant is safe for all fish in freshwater or saltwater aquariums. It won’t crack or shrink, also suitable for use with metal, ceramic, and concrete.


  • Remains flexible
  • Versatile use
  • Good for the less handy aquarists


  • Small size

6. Marineland: Easy Application for Effective Sealing

MarineLand Fish & Aquatic Supplies Silicone Sealer 1 oz (Tube)
Get Marineland Silicone Squeeze Tube

Last but not least, the MarineLand Silicone Squeeze Tube is a clear 100% silicone sealant that’s specifically formulated for aquarium use. It delivers a solid bond with an impressive grip that dries pretty quickly to save you the hassle of waiting.

The MarineLand silicone sealant stays flexible even underwater. It comes in a sturdy tube so it won’t easily burst out like other brands. However, the long, narrow nozzle can make the application a bit tricky.


  • Study packaging
  • No irritating odor
  • Good value for money


  • The nozzle is a bit too narrow

Selecting the Ideal Silicone for Your Aquarium: A Comprehensive Guide

When it comes to creating a safe and secure environment for your aquatic life, high-strength silicone is an indispensable tool in your arsenal. One such reliable product is the ASI Aquarium Silicone Sealant. This silicone sealant offers exceptional bonding capabilities and is specially formulated for aquarium use, ensuring the safety and well-being of your marine and freshwater companions.

In your quest for the perfect aquarium silicone, mildew and mold inhibitors should be high on your checklist. These additives are crucial for preventing the growth of harmful microorganisms that could threaten the health of your aquatic friends.

Aquariums are subjected to a range of environmental conditions, including constant operating temperatures and exposure to ultra-violet radiation. That’s where silicone products like GE Silicone shine. They exhibit excellent resistance to these factors, guaranteeing a long-lasting seal that can withstand the test of time.

For enthusiasts of salt-water aquariums, silicone selection becomes even more critical. These environments demand a silicone that is not only durable but also highly resistant to the corrosive nature of marine life. It’s essential to choose a silicone that can endure the challenges presented by salt-water aquariums.

Mastering Silicone Application for a Secure Aquarium

Now that you’ve selected the right silicone for your aquarium, it’s time to master the art of applying it effectively. The first step is clean glass preparation. Before you even think about applying silicone, ensure that the glass surfaces are thoroughly cleaned and free from any contaminants. A small dollop of silicone won’t adhere well to dirty glass.

When it comes to applying silicone, bead size matters. Understanding the correct bead size for your application is crucial. Too much or too little can result in improper sealing, which can compromise the integrity of your aquarium.

Aquariums often feature a variety of surfaces, including vertical and horizontal surfaces, not to mention sump baffles. Each of these surfaces requires a specific approach when applying silicone to ensure a strong bond.

For those eager to set up their aquarium quickly, silicone with a quick cure time is a game-changer. This feature allows you to expedite your new aquarium setup without sacrificing the quality of the bond.

Moreover, silicone isn’t a one-size-fits-all solution. It’s essential to understand how to use silicone for different purposes within your aquarium, such as sealing the bottom of the tank or repairing leaky fish tanks.

Ensuring a Durable and Strong Bond in Aquarium Construction

To achieve a strong and lasting bond, consider using a high modulus component RTV silicone sealant. This type of silicone is known for creating cohesive bonds that are incredibly resilient.

Understanding the distinction between neutral cure and acetic acid cure silicone is crucial. Each type has its advantages and applications in the aquarium environment, and choosing the right one can make a significant difference in your project’s success.

Before applying silicone, always check for the presence of contaminants on the surfaces. Any residues or impurities can hinder the bonding process and compromise the effectiveness of the silicone seal.

Prioritizing Safety and Health in Your Aquarium Setup

The well-being of your aquatic life and aquarium friends should be a top priority. Using the right silicone is essential in ensuring their safety. Aquarium-safe silicone, such as ASI Aquarium Silicone Sealant, is formulated to meet the specific requirements of the aquarium hobby.

Consider the long-term effects of your choice in silicone. The right silicone not only creates strong bonds but also maintains its integrity over time. This is particularly important for reef tank enthusiasts who need a reliable seal for their delicate ecosystems.

In some cases, using a silicone release agent may be necessary. This substance helps in preventing unwanted adhesion and makes working with silicone in the aquarium environment more manageable.

Where to Shop for High-Quality Aquarium Silicone

You might be wondering where to find these specialized silicone products. Your local hardware store, including well-known retailers like Home Depot, can be a valuable resource. They often stock a range of aquarium-safe silicone sealants, allowing you to make an informed choice.

Additionally, online shopping offers convenience and a wide selection of silicone products tailored for aquarium use. Many online retailers offer free shipping and speedy delivery times, making it a hassle-free option for acquiring the silicone you need.

When shopping for silicone, consider the perfect size for your project. Whether you need small tubes for quick household repairs or larger tubes for significant aquarium projects, choosing the right size ensures you have the perfect amount of silicone on hand.

For those looking for a trusted brand, explore the quality and availability of Apel’s Aquarium Sealant. This brand has earned a reputation for its excellence in the aquarium hobby.

Maintaining and Repairing Your Aquarium with the Right Silicone

After successfully applying silicone to your aquarium, the journey doesn’t end there. Regular maintenance is essential to ensure the longevity of your aquarium’s seals. Periodically checking and resealing your aquarium with the right silicone is a proactive approach to preventing potential leaks and issues.

Beyond the aquarium, quick household repairs can also benefit from aquarium silicone. Its versatility and quick cure time make it a handy tool for various applications in and around your home.

Should you ever need to make changes or repairs, knowing how to safely remove uncured silicone from glass surfaces is essential. Improper removal can damage the glass and create more significant problems down the line.

Final Thoughts: The Role of Silicone in Aquarium Care

In conclusion, choosing the right aquarium silicone product is a critical step in maintaining a healthy and leak-free aquarium. The use of high-strength silicone with mildew and mold inhibitors, resistance to environmental conditions, and suitability for salt-water aquariums ensures the safety of your aquatic life.

Mastering proper application techniques, including clean glass preparation, bead size considerations, and addressing various surface types, is key to achieving a strong and long-lasting bond. Understanding the differences between neutral cure and acetic acid cure silicone, as well as checking for contaminants, further enhances the effectiveness of your silicone seal.

Prioritizing safety and the well-being of your aquatic companions is paramount. The long-term effects of aquarium-safe silicone and the occasional need for a silicone release agent should not be overlooked.

Whether you source your silicone from a local hardware store like Home Depot or opt for the convenience of online shopping, choosing the perfect size and considering reputable brands like Apel’s Aquarium Sealant are crucial steps in your aquarium project.

Remember that maintenance and repairs are ongoing tasks. Regular check-ups and proactive resealing will help ensure the lasting bonds created by your chosen silicone products.

In the world of aquariums, the right silicone is more than just a sealant; it’s a safeguard for the aquatic life you cherish, creating a secure and thriving underwater world.

Summary: The Essential Role of Aquarium-Safe Silicone

It’s rather evident that aquarium safe silicone sealants are a must-have item for any serious aquarist, and so, you should be very careful when shopping for the right sealant.

Make sure your silicone sealant comes from a reputable brand to guarantee the utmost credibility. Also, remember to thoroughly check the label for any harmful components as we mentioned above.

Aquarium Safe Silicone

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