The 9 Best Aquarium Silicone Sealants to Buy in 2024

Quick Facts:

• Type: Made specifically for aquarium use
• Volume: 10.2 fl oz
• Color: Clear, black
• Cure time: 10 days

Size & Color

Ideal for those with large aquatic set-ups, this sealant is rated for use in tanks up to a whopping 750-gallon capacity. This is the highest capacity rating we’ve seen, and it’s not particularly close, either. It comes in a sizable 10.2 fl oz size bottle, but a caulk gun is necessary for use. You’ll need to factor this into your pricing considerations – but of all the products reviewed, only GE Silicone 1 beats out ASI on $-per-oz value.

ASI’s sealant is available in both transparent and black color variations, the latter being excellent for those wishing to match existing black seals, which are increasingly popular on new, store-bought tanks. Plus, we find the black version is great for hiding algae, and the added colorant isn’t prone to flaking – sometimes an issue with other black silicones.

Adhesion

Simply put, it’s the best multi-use silicone we’ve seen: strong enough to seal glass panels or fix large cracks, without being overkill for use on small chips or decorative repairs. By comparison, most other products can only excel in one area.

We consider this the stand-out choice if you’re looking for silicone to use on multiple tanks, or a do-it-all product to reseal panels as well as fix small issues. Impressively, it also bonds well to acrylic tanks, something most other aquarium silicones simply can’t do. In fact, according to ASI’s in-house testing, this silicone can hold together a 700-gallon acrylic tank without issue.

Ease of Application

ASI’s silicone has a stiffer consistency than most other silicones, which we find makes it ideal for vertical seals because it doesn’t flow away from the application site. This stiff consistency also makes spillages and misapplications much less likely than with more viscous silicones. Plus, it starts to set rapidly, which allows you to work at a fast pace. The trade-off? It’s more likely to stick to your fingers, so we advise wearing a pair of gloves during use.

Cure Time

Although it starts to set quickly, this product takes a long time to fully cure – up to 10 days. This means rehoming your fish for a significant amount of time, and while the quality is worth the wait, it will give off silicone’s characteristic vinegary smell throughout.

Quick Facts:

• Type: Multi-purpose, aquarium safe
• Volume: 2.7 oz
• Color: Clear
• Cure time: 24 hours

Size & Color

Loctite Clear Silicone is sold in a small, 2.7 oz tube. This may feel tiny, but in our experience, it’s still more than sufficient for those with average-sized aquariums who only need to fix a small leak. Used this way, you’ll still get plenty of use from a tube this size. Notably, it shouldn’t be used to seal aquariums with a water capacity above 30 gallons.

Adhesion

Loctite Clear Silicone does an excellent job of adhering to tank glass, and it’s ideal for those needing a small amount of silicone on hand for emergencies, or for precise gluing of small decorative objects. It’s also a convenient product to have around the home for other DIY work, as it bonds well to stainless steel, wood, porcelain, and fiberglass.

Ease of Application

There’s no caulking gun required here; the simple squeeze-tube makes this very beginner-friendly. Plus, it comes with a removable pinpoint tube head, which is incredible for precise application. Unfortunately, this applicator is prone to clogging after a couple of uses and you may have to resort to application directly from the tube. If so, go light when squeezing, as in our experience these tubes tend to burst rather easily.

Cure Time

This stuff cures very quickly. In our experience 24 hours is all it takes – that’s up to 9 days sooner than with ASI Aquarium Sealant. If you’re looking to quickly repair a minor issue in a small tank, you can’t go wrong here.

Quick Facts:

• Type: Multi-purpose, aquarium safe
• Volume: 3 oz
• Color: Clear
• Cure time: 1 hour

Size & Color

JB Weld is a clear-colored silicone that comes in one size – a small, 3 oz tube. While we believe its performance does justify the price, bear in mind that it typically costs in excess of $3 per oz.

WARNING: While JB weld offers silicone in 8 different colors – only the ‘Clear’ version is indicated for aquarium use. All other variations contain additives that can harm aquatic life.

Adhesion

The closest competitor for JB Weld is Loctite Clear Silicone. In terms of adhesion, they’re equally impressive and there’s no noticeable difference in their strength or consistency. As with Loctite, it’s only suitable for smaller repair projects, though.

Ease of Application

JB Weld comes with a removal applicator head, making application beginner-friendly, even for tricky chips or hard to reach interior spots. In our experience, this applicator head is less prone to clogging than Loctite, although the squeeze-tube is equally as likely to split under excessive pressure.

Cure Time

JB weld only takes a single hour to cure, faster than any other product we’ve seen. This curing speed offered is phenomenal and perfect for making a small seal fix in a pinch. This benefit should not be underrated and means you won’t need to find a longer-term solution for rehoming your fish, and can get your normal set-up back together in a single afternoon.

Quick Facts:

• Type: Made specifically for aquarium use
• Volume: 1, 3, and 10.4 oz
• Color: Clear, black (3 oz only)
• Cure time: 48 hours

Size & Color

For the standard ‘clear’ color, Aqueon is available in 3 different sizes. The 3 oz version is also available with black colorant, which is a nice touch. We love these sizing choices as they’re much more likely to work out as cost-efficient for your use and result in less product wastage. For a rough idea, on a small aquarium (~10 gallons) a 3 oz tube is sufficient to cover all seals 2-3x over.

Adhesion

Made by aquatic specialists Aqueon, this product is designed specifically for use within glass aquariums and is ideal for repairing structural leaks. It has high tensile strength and is suited for use sealing sizable leaks, without requiring a long cure time, or being sold solely in large, caulk tubing. We’ve seen no other product that offers size/color variations as well as being strong enough to handle significant leaks, without the need of a caulk gun.

Ease of Application

Be ready for this silicone to come out of the bottle with a softer, more flowing consistency than you may expect. Things can get messy if you over-apply, but as long as you’re measured in your application, we still expect most beginners to find this simple enough. Just watch out for the screw cap on the tiny 1 oz tube, we find it’s prone to breaking if overtightened.

Cure Time

Aqueon advises leaving 48 hours for a full cure, longer than small-fix options like JB Weld, but still impressive for the tensile strength it offers. By comparison, many other silicones that are also strong enough for resealing panels, like Momentive or ASI Aquarium Sealant, take 7-14 days to cure.

Quick Facts:

• Type: Not indicated for aquarium use, but a time-tested favorite amongst aquarists
• Volume: 10.1 oz
• Color: Clear
• Cure time: 12-24 hours

Size & Color

GE Silicone 1 comes in a 10.1 oz tube, which applies white but after curing takes on the typical translucent appearance. There’s no size choice here, but this seems less important when you consider that it usually only costs between $0.4-0.6 per oz.

Adhesion

As per the disclaimer below, GE Silicone 1 isn’t designed for aquarium use. Still, it’s a time-tested favorite as a general-purpose silicone amongst aquarists. We wouldn’t suggest using it to seal glass panels as the strength is unlikely to hold up well over the long-term – it feels a little too risky for our tastes. But it’s an excellent adhesive for interior work and fixing up small chips and cracks.

Ease of application

You need a caulk gun to apply it, and because it’s not designed specifically for aquarium use it’s rather thick, making application tough, especially for beginners. More positively, it boasts an impressive shelf-life of 24 months- so it’s unlikely to go to waste and you can always use any remaining silicone for other DIY projects, it is made for window and door projects, after all.

Cure Time

GE suggests waiting 12 hours before water exposure, although in accordance with the below disclaimer, we would suggest that you add an extra 12 hours of cure time on top of that, as an extra precaution.

DISCLAIMER: As this product contains 1-5% D4 (octamethylcyclotetrasiloxane), a warning against aquarium use is included in the product safety information. D4 can leach into the water and bioaccumulate, which over time, may limit fish growth and reproduction. By comparison, aquarium-grade silicones have <0.2% D4 by weight. That said, serious fish keeping hobbyists, aquarists, and aquarium building companies have used this product for many years – with no reported reduction in fish growth or life expectancy. As long as it is left to cure before submersion, it’s widely considered to be inert.

Quick Facts:

• Type: Made specifically for aquarium use
• Volume: 4.7 or 10.1 oz
• Color: Clear, black
• Cure time: 30 minutes (48 hours recommended)

Size & Color

Aquascape is available in either a 4.7 oz squeeze-tube or a 10.1 oz caulk tube, in both clear and black colors. As with Loctite Clear Silicone and JB Weld, we find the 4.7oz tube prone to splitting, a common theme for silicone squeeze-tube designs.

Adhesion

Unlike any other aquarium silicone reviewed, Aquascape has been formulated with specific aquatic tasks in mind. For example, as well as aquariums Aquascape was designed to prevent leaks in other aquatic systems like outdoor ponds, too. If, like many hobbyists, you keep fish outside, as well as inside the home, this may be just the ticket.

Aquascape was also made to flawlessly seal liners to Aquascape Biofall Filters and skimmer boxes. So if improving filtration is a priority for you, Aquascape silicone is an easy choice.

Ease of Application

While it’s as easy to apply as any other silicone to make our list, we do find there’s more potential for eye/nose irritation during application. While this won’t do any serious harm, mask use is advised here.

Cure Time

Officially, Aquascape requires you to wait 30 minutes before water contact, but we find this is well short of the mark for constant submersion. We wouldn’t risk less than 48 hours, especially for larger cracks or full panel seals.

Quick Facts:

• Type: Multi-purpose, aquarium safe
• Volume: 2.8 oz
• Color: Clear
• Cure time: 72 hours

Size & Color

Dap comes in a 2.8 oz squeeze-tube and with a typical transparent color. This tube size is excellent for precision gluing but not suitable for bigger jobs that require greater tensile strength – it simply wouldn’t hold up over the long term, and even if it did, would require too many tubes to be a cost-efficient choice.

Adhesion

For small chips and cracks, Dap is more than fit for long-lasting and watertight glass adhesion, despite having no real stand-out attributes compared to other aquarium silicones. It gets the job done, though, and that’s all you can really ask.

Ease of Application

We find Dap takes a little longer to set than other silicones reviewed, so mistakes are simple to rectify and you won’t need to panic about small misapplications. It also comes with a very long, fine applicator nozzle that makes a tidy, precise application simple. For these reasons, we consider it to be the most beginner-friendly aquarium silicone currently available.

PRO-TIP: the applicator nozzle has no cap, so you may find that it seals closed after one use. To prevent this, use a toothpick after each use to remove silicone from the tubing before it sets.

Cure Time

Dap takes 72 hours to fully cure, longer than it’s closest competitors, Loctite Clear Silicone and JB Weld. Unfortunately, Dap also has a sharper acetic acid scent while curing, which you can expect to linger for at least a few days.

Quick Facts:

• Type: Made specifically for aquarium use
• Volume: 1, 3, and 10.3 oz
• Color: Clear
• Cure time: 24-48 hours

Size & Color

Marineland offers 3 sizes of transparent aquarium silicone: 1 oz and 3 oz squeeze-tubes and a 10.3 oz caulk tube. Our advice would be to skip on the 10.3 oz size – if you need this much silicone you’re likely undertaking a sizable project and there are better options for this purpose. But the tiny 1 oz and the 3 oz tube are our favorite choices for aquarium ornament repair and decorative touch-ups.

Adhesion

Our experience shows that MarineLand silicone offers sufficient adherence for small interior repairs, but it’s not durable enough for seal work or to repair large cracks. While some aquarists do choose to use MarineLand to seal their aquariums, this is not something we can comfortably recommend for long-term success.

Ease of Application

MarineLand has the best squeeze-tube of all the products to make our list. All other squeeze-tube designs tend to split at some point before the product is finished, but this is much less likely with MarineLand Silicone. We’re not sure if it’s the packaging itself or the silicone formulation inside, but either way, we’re not complaining.

Unfortunately, we find the nozzle often isn’t broad enough for applying a sufficient width of silicone in one pass. As such, you’ll have to go over the same area several times. This is fine for smaller aquariums or when applying to aquarium decoratives, but will significantly bump up treatment time for more elaborate set-ups.

Cure Time

24-48 hours is the suggested curing time, which puts it in the middle of the pack against the competition. Similarly to Dap All-Purpose Adhesive Sealant, it has a stronger than normal odor during curing, but this will dissipate entirely by the time it’s fully set.

Quick Facts:

• Type: Not indicated for aquarium use, but a time-tested favorite amongst aquarists
• Volume: 10.1 oz
• Color: Clear
• Cure time: 7-14 days

Size & Color

Momentive is sold in a 10.1oz caulk tube, but is also offered in 2-, 3-, or 4- pack bundles for extra savings on bigger jobs. These bundles are ideal for professional tank builders, or hobbyists with elaborate set-ups who are looking to take their passion for fishkeeping to the next level. As standard, it applies white but becomes transparent once cured.

Adhesion

This is the strongest silicone adhesive of every product to make our list, hands down. It’s routinely used by professional tank builders to seal full glass panes, as the tensile strength is sufficient enough to support even the largest tanks. If you’re a serious hobbyist looking to build an additional aquarium or undertake a serious repair, or a professional looking for the absolute best seal quality available – this should be your go-to.

Ease of Application

Unless you consider yourself to be particularly handy, we can’t recommend Momentive for first-timers. It requires a caulk gun and the consistency of the silicone paste is the thickest we’ve seen, plus it starts to set within minutes. As a result, mistakes are tricky to rectify and accurate application is essential.

Cure Time

Momentive takes a long time to cure fully: at least 7 days, ideally 14 for larger jobs. Long-term you’ll be rewarded with incredible seal longevity but it’s certainly not for those in a rush to get a DIY project completed.

DISCLAIMER: As this product contains 1-5% D4 (octamethylcyclotetrasiloxane), a warning against aquarium use is included in the product safety information. D4 can leach into the water and bioaccumulate, which over time, may limit fish growth and reproduction. By comparison, aquarium-grade silicones have <0.2% D4 by weight. That said, serious fish keeping hobbyists, aquarists, and aquarium building companies have used this product for many years – with no reported reduction in fish growth or life expectancy. As long as it is left to cure before submersion, it’s widely considered to be inert.