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6 Best Aquarium Silicones 2021 – Reviews & Top Picks

Nicole Cosgrove

African Cichlid Fish Tank

In a perfect world, it’s

a product that you wouldn’t need to buy. However, sometimes you must get aquarium silicone if your tank develops a leak. It can happen with an older tank where the sealant cracks with age. Perhaps, you want to make a custom aquarium and wants something to seal the glass panels together reliably.

Silicone has many applications outside of using it for your fish tank. They range from kitchen utensils to insulation to even Silly Putty. These uses mean that not all products are the same. What you can use in the garage is not necessarily the same one you can use on your aquarium. Our guide will discuss the different items available, along with reviews of what you can find.

We’ll explain what aquarium silicone is and how to apply it for the best results from emptying the tank to putting the fish back inside of it.

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A Quick Comparison of Our Favorites

Image Product Details
Best Overall
Winner
Aqueon Silicone Aquarium Sealant Aqueon Silicone Aquarium Sealant
  • Convenient size
  • Affordably priced
  • Suitable for both fresh and saltwater
  • Best Value
    Second place
    ASI Clear Aquarium Silicone Sealant ASI Clear Aquarium Silicone Sealant
  • Appropriate for fresh or saltwater use
  • Excellent consistency
  • Long tip for easy application
  • Premium Choice
    Third place
    Dap All-Purpose Adhesive Sealant Dap All-Purpose Adhesive Sealant
  • Aquarium safe
  • 100-percent silicone
  • All-purpose product
  • Loctite Clear Silicone Waterproof Sealant Loctite Clear Silicone Waterproof Sealant
  • Works on a variety of materials
  • Affordable price
  • Suitable size
  • Aquascape Black Silicone Sealant Aquascape Black Silicone Sealant
  • Separate applicator cap
  • Aquarium safe
  • The 6 Best Aquarium Silicones – Reviews 2021

    1. Aqueon Silicone Aquarium Sealant – Best Overall

    Aqueon Silicone Aquarium Sealant

    The Aqueon Silicone Aquarium Sealant has a lot going for it. It’s affordable and comes in a size for small jobs to reduce waste. The product works as described with a 48-hour curing time. It’s easy to work with and has a closure that can extend its useful period. It comes in both clear and black to match the use. On the downside, there are some quality control issues with packaging.

    The product works well with glass, but you can’t use it on acrylic. That takes it off the table for customized setups. However, it’s only a dealbreaker in those cases. Otherwise, the sealant does the job well.

    Pros
    • Convenient size
    • Affordably priced
    • Suitable for both fresh and saltwater
    Cons
    • Appropriate for glass only

    2. ASI Clear Aquarium Silicone Sealant – Best Value

    ASI Clear Aquarium Silicone Sealant

    If you’ve got a big job or are making a customized tank, the ASI Clear Aquarium Silicone Sealant is the best aquarium silicone for the money. You’ll have enough sealant to take care of a large tank or several with one purchase with the 10-ounce tube. It has a long tube for getting into corners without worrying about messing up the line of the bead. It comes in both clear and black, too.

    Pros
    • Appropriate for fresh or saltwater use
    • Excellent consistency
    • Long tip for easy application
    Cons
    • Long curing time up to 10 days, depending on the humidity
    • Strong smell

    3. Dap All-Purpose Adhesive Sealant – Premium Choice

    Dap 00688 All-Purpose Adhesive Sealant

    If you’ve worked in the construction industry or have done DIY projects, the name of this manufacturer is undoubtedly familiar to you. Its reputation in that field is sometimes less than a stellar statement about the user. As an aquarium silicone, it ticks off the right boxes. It is labeled for this use, which we appreciate to differentiate it from other products in the company’s line.

    The highlights of this sealant are that it’s food-safe for a variety of projects, and it works on acrylic, too. The fact that it is a one-time-use-only silicone puts it squarely in the dealbreaker category.

    Pros
    • Aquarium safe
    • 100-percent silicone
    • All-purpose product
    Cons
    • One-time use only
    • Unpleasant odor

    4. Loctite Clear Silicone Waterproof Sealant

    Loctite Clear Silicone Waterproof Sealant

    The manufacturers of the Loctite Clear Silicone Waterproof Sealant do it right. Yes, it’s a product to use on fish tanks. However, it is also appropriate for a plethora of other applications, yet it’s labeled to reflect its safety for aquariums to avoid any confusion. The downside is that you can’t use it for tanks bigger than 30 gallons because of the lack of tensile strength.

    On the positive side, you’ll get your money’s worth out of your purchase because of its versatility. Unfortunately, the packing is lacking, which makes that second use questionable.

    Pros
    • Works on a variety of materials
    • Affordable price
    • Suitable size
    Cons
    • Clear only option
    • Use for aquariums up to 30 gallons only
    • Poor packaging

    5. Aquascape Black Silicone Sealant

    Aquascape Black Silicone Sealant

    The name of the Aquascape Black Silicone Sealant tells you upfront what you need to know. This product comes in two sizes, 4.7 and 10.1 ounces. Both are too much for small jobs. It comes in both clear and black. There are two caps, which we appreciated to at least get the most out of storing it in-between uses.

    On the downside, the two available sizes are too big for a small job so that you will waste a lot of product. It does have a second cap, which we appreciated.

    Pros
    • Separate applicator cap
    • Aquarium safe
    Cons
    • Available sizes lead to waste
    • Expensive

    6. MarineLand Aquarium Silicone Sealant

    MarineLand Aquarium Silicone Sealant

    The MarineLand Aquarium Silicone Sealant was the only product we reviewed that came in a 1-ounce tube. That is so convenient if you’re repairing a small leak. It only comes in clear, which is a bummer if you need something different. The product worked as described, although it is expensive for having it available in this size.

    The silicone is only available in clear, which is too bad if the sealant is a part of the design. The cap and consistency of the product are not the best. You’ll likely have a mess on your hands if you handle it improperly.

    Pros
    • Smaller size available
    Cons
    • Very expensive
    • Clear color only
    • Not user-friendly

    Buyer’s Guide

    Let’s begin by discussing what silicone is. Essentially, it is a chemical compound or polymer consisting of silicon and oxygen. It gets its tensile strength from the addition of silica. The material is an excellent choice for fish tanks for several reasons. Silicone is one of the few compounds that form durable bonds to the glass. The seals are watertight, too.

    Aquarium silicone dries clear once it’s done curing. Aesthetically, that makes it very pleasing for creating a natural-looking aquatic environment. However, you’ll also find it in several colors for similar uses. The essential thing to understand is that not all products are suitable for aquarium use. Sealants used for other purposes, such as plumbing, may contain additives that are harmful to fish and plants.

    Things to consider when buying aquarium silicone include:

    • Aquarium safe
    • Curing time
    • Ease of use

    Aquarium Safe

    You may think that this factor is a no-brainer, but it’s worth mentioning. You’ll find silicone in several retail outlets other than pet stores. You may even see some marked waterproof for bathroom use. Products that aren’t meant for aquarium use might contain other additives like fungicides. The problem is that they may leach chemicals into the water that are toxic for fish.

    Remember that the tank is your fishes’ environment. You’re in control. That means that you have to ensure that nothing is potentially harmful gets into the water. After all, that’s why you have a filter for your aquarium to keep it clean and a siphon to drain out the debris in the gravel occasionally.

    Fortunately, you’ll find silicone that specifies that it’s safe for aquarium. Products meant for ponds are suitable, too. A pond is essentially a large aquarium, typically with goldfish or koi. Make sure that you get one that is labeled for either use.

    Curing Time

    The fact remains that this type of sealant requires time to cure and harden while still retaining some degree of flexibility. Yes, it is a pain to drain the tank, set up a place for your fish, and get it going again. Depending on the formulation, you can expect it to take anywhere from 24 hours to several days. We strongly urge you to wait for the recommended time.

    Don’t rush it. Otherwise, your aquarium may leak if it doesn’t have the proper seal.

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    Ease of Use

    This consideration covers a lot of bases. First, think about how much silicone you need for the job. It’s a critical factor when choosing the right size.

    How Much Do You Need?

    You don’t need 10 ounces of the stuff if there is only a small leak. There’s the cost difference, but there is also the waste. Silicone probably isn’t something you use every day. The tube will likely dry out before you need it again.

    Look at the Applicator

    Second, look at the applicator. Silicone is messy. There’s no way of getting around it. We appreciate it if manufacturers at least try to make the best of it. The good news is that you have time to make it right since it doesn’t dry right away. That’s a good thing about the curing time. It gives you time to work. We suggest reading the fine print about specs like drying time and shelf life.

    One-time vs Multiple-use

    Also, find out if it’s a one-time use an only product or one that you can use multiple times. This feature plays right into the ease of use. Bear in mind that the sealant will expand due to temperature differences. If you’re storing it in the garage, it might become unusable. Because of this variability, we recommend getting aquarium silicone in a size that is appropriate for the job.

    The Odor Issue

    We also have to address the elephant in the room. Silicone stinks, but some products are worse than others. Manufacturers try to make it less unpleasant. Rest assured that it doesn’t last. It’s usually only noticeable when you apply it. If it really bothers you, do the work outside so that it’s not an issue. Besides, the better light can help you apply it correctly. Make lemonade out of lemons.

    Colors

    Most often, you’ll see aquarium sealants available as clear only. Many people use it for other projects, like vivariums. Therefore, you may also find it in other colors, most often black. It is useful for creating borders and distinct lines that are attractive for customized projects. However, that also means you must take care in its application.

    Using something other than clear puts the spotlight on your job. Just saying.

    Using Aquarium Sealant

    While the packaging and applicator look user-friendly, the use is more involved. The fact is that you must start with a clean slate. We are talking about leaks. Don’t skimp on it. Remember what is involved with the process, like emptying the tank, displacing your fish… Here are four tips for using aquarium sealant:

    1. Make it easy for yourself. Do the job right from the start, even if it seems like a pain. Fortunately, you’ll find that the old sealant comes off easily with a razor blade. A clean surface is the best way to ensure that the new layer will adhere. That speaks to one of the biggest complaints that buyers have with aquarium silicone. Sorry to say, but it’s user error.
    2. Once you’ve removed the old stuff, wipe the surface clean. The object is to have the silicone stick to the sealant and not the debris or leftover sealant on the glass. Remember that you have some time when you line the seams and aligning it since it isn’t like the small window you have with Super Glue. We’d suggest avoiding touching the silicone as much as possible.
    3. Our other recommendation involves curing time. The sealant isn’t glue. That’s why you’ll see this wait-time recommendation. The time depends on the composition of the product. Safe to safe that you’ll have to wait at least one day. We always like to give it an extra day or two, considering its purpose. Test it with a touch test.
    4. It should feel solid and not sticky. Bear in mind that it will take longer to cure if the relative humidity is high. Also, the thickness of your application can affect drying time. We suggest running a razor over the bead to even it out and speed the curing.

    Conclusion

    In our opinion, the best aquarium silicone for the buck is Aqueon Silicone Aquarium Sealant. The price is right in a size that is convenient for small jobs. It’s easy to use in a size that is ideal if you just have a little leak to fix. It is easy to use without an offensive odor. It’s a cheap and quick fix. The essential thing is to do it right. Use the right product. Apply it properly. Give it time.

    For more info on Aquarium gear, check out these posts:


    Featured Image: Wikimedia Commons/ Wikipedia

    Nicole Cosgrove

    Nicole is the proud mom of Baby, a Burmese cat and Rosa, a New Zealand Huntaway. A Canadian expat, Nicole now lives on a lush forest property with her Kiwi husband in New Zealand. She has a strong love for all animals of all shapes and sizes (and particularly loves a good interspecies friendship) and wants to share her animal knowledge and other experts' knowledge with pet lovers across the globe.