Guide to Aquarium Glue for Glass

Setting up and maintaining an aquarium requires carefully sealing all the components to create a fully watertight environment. Using the proper adhesive for glass aquariums is crucial to securely bond the glass panels and affix accessories. With so many glue products available, choosing the right one can get confusing.

This guide covers selecting, using, and applying aquarium glue for glass tanks and decorations. Read on for the best glass glues and tips for flawless underwater bonding.

An Introduction to Aquarium Glue

Glue might not seem like the most exciting aquarium topic, but having the right adhesive is essential for building a safe, stable, attractive tank. Here’s a quick primer on why aquarium glue matters:

Creates Strong Seals – Glue binds glass panes together to create leakproof seals that withstand thousands of gallons of water pressure.

Bonds Accessories – Adhesives affix decorations and hardware inside the tank. This allows you to aquascape with rocks, driftwood, and more.

Repairs Damage – Glue can patch small cracks, leaks, and broken equipment to extend your tank’s life.

Prevents Disasters – Proper seals prevent catastrophic tank failures that could harm pets and damage your home.

So glue helps hold your underwater world together both literally and figuratively! Let’s explore the types of adhesives commonly used in aquariums.

Types of Aquarium Glues for Glass

The two main categories of aquarium glue for glass applications are silicone and acrylic-based products. Here’s an overview of each type:

Silicone-Based Aquarium Glues

Silicone is the most common aquarium glue used today. Silicone chemically bonds extremely well to glass, making a watertight seal. It remains flexible over years of use, accommodating temperature changes and natural movement of glass panes. Brands like ASI Silicone Sealant and Aqueon Silicone Sealant are silicone-based products for aquariums.


  • Strong, flexible bonds to glass
  • Withstands water, heat, and temperature fluctuations
  • Specialized aquarium varieties available
  • Clear finish blends in discreetly


  • Difficult to apply smoothly for beginners
  • Not for use on acrylic or plastic tanks
  • Fumes require proper ventilation

Silicone glue is the top choice for glass fish tanks, terrariums, and paludariums. With the right safety practices, it creates reliable seals that last.

Acrylic-Based Aquarium Glues

Acrylic solvent cements are required instead of silicone for bonding acrylic plastic pieces. Brands like Weld-On #16 Acrylic Adhesive make durable bonds by chemically fusing acrylic surfaces as the glue cures. The joint formed is almost indistinguishable.


  • Provides extremely strong acrylic-to-acrylic bonds
  • Dries clear for invisible seals
  • Sets up quickly compared to silicone


  • Only works on acrylic, not glass or other plastics
  • Gives off strong fumes requiring ventilation
  • Joints can crack over time if stressed

For acrylic tanks or decorations, acrylic cement is mandatory. It cannot be replaced with silicone or other glue types. Proper safety precautions are essential when using acrylic solvents.

Key Considerations for Choosing Aquarium Glue

With different glue types available, there are a few key factors to evaluate so you choose the best product for your specific needs:

Intended Bonding Materials

Ensure the glue is designed for and chemically compatible with the materials you want to bond – glass, acrylic, etc. Using the wrong glue can mean weak bonds or no adhesion.

Water and Moisture Resistance

When fully submerged, the glue must maintain strong bonds and not weaken or dissolve. Verify waterproof ratings before use in aquariums.

Temperature Tolerance

It should withstand temperature fluctuations from equipment and room conditions. Check adhesive specs for operating ranges.

UV Light Resistance

When used in exposed areas, glue should not yellow or degrade under intense aquarium lighting. Opt for UV-resistant varieties.

Curing Time

Faster-curing glues allow you to complete projects quickly while slower-curing ones give you more time to adjust bonds before they set.


Crystal clear glue blends in seamlessly. But some epoxies and silicones may cure slightly cloudy. Sample colors before use.


Non-toxic adhesives are essential for inhabitant health. Read labels to verify aquarium-safe glues.

Remembering these adhesive selection criteria, you’ll find the right glue to create safe, secure bonds throughout your aquarium.

Types of Glue for Specific Aquarium Materials

Now let’s take a closer look at recommended glue types for some common aquarium construction projects:

Glass to Glass

Silicone aquarium sealant

Creates a flexible, waterproof seal between glass panes or panels. Withstands long-term water exposure and heat.

Glass to Acrylic

Two-part epoxy adhesives

Can bond glass and acrylic together in decor projects. Let epoxy cure fully before water contact.

Acrylic to Acrylic

Acrylic cement

Fuses acrylic pieces together at a chemical level. Required for acrylic tanks and fittings.

Glass to Plastic

Cyanoacrylate super glues

Effective on plastics like airline tubing and 3D printed parts. Use gel formulas to fill gaps.

Rocks/Driftwood to Glass

Silicone aquarium sealant

Affixes decor securely to glass while allowing some movement. Strengthened over time.

Rocks to Rocks

Submersible epoxy putties

Allows multi-piece rock structures. Putty cures fully when immersed in water.

This covers some of the most common aquarium glue applications. Always read labels to verify compatibility and safety.

Step-by-Step Guide to Applying Aquarium Glue

Once you’ve selected the appropriate aquarium glue for your project, proper application technique is equally important for flawless results. Follow this step-by-step process:

1. Clean Surfaces

Remove any dirt, oil, or debris so the adhesive bonds directly to the material. Wipe glass with vinegar and let dry completely.

2. Prepare Workspace

Cover areas to protect from spills. Arrange all glue components, tools, rags, and materials before starting.

3. Cut Nozzle

Cut the applicator nozzle at a 45° angle to desired tip opening size. This controls glue flow.

4. Apply Glue

Squeeze out glue smoothly and evenly onto one bonding surface. Use even pressure and beads for silicone.

5. Mate Surfaces

Press surfaces together within open time limits. Clamp or brace parts to prevent movement while curing.

6. Clean Up

Wipe away any excess glue before curing using a rag soaked in mineral spirits. Remove clamps after prescribed cure time.

7. Allow Full Cure

Wait the full cure time listed on the glue packaging before submerging. Never rush this step.

Follow these tips closely to create strong, lasting, and attractive aquarium glue bonds that withstand the test of time… and water!

Using Aquarium Glue for Securing Rocks and Decorations

One extremely useful application for aquarium glue is adhering rocks, driftwood, and decor items in your tank. Here are some tips for decorative glue jobs:

Select Appropriate Glue

For rocks and driftwood, use non-toxic silicone sealant rated for full submersion. Avoid super glues.

Plan Decor Layout

Figure out the structure and where/how pieces bond together before starting.

Clean and Dry Surfaces

Free of debris, oil, algae coatings for max adhesion. Let fully dry.

Apply Glue Sparingly

Use small dots and lines – less is more. This allows some natural movement.

Allow Full Curing

Give glue several days to cure fully before filling tank. Slow immersion is better.

Check Seals Periodically

Inspect bonds routinely for signs of loosening or leaks. Re-glue if needed.

With good planning and application, aquarium glue lets you create themed rock structures and decor scenes that stay securely in place long-term.

Can Any Silicone Be Used for Aquarium Seals?

You may be tempted to grab whatever silicone caulk you have in the garage to re-seal your aquarium rather than buy a specialty product. But it’s critical to only use silicone formulated for aquarium use.

Why Regular Silicone Fails

Hardware store silicone caulk, even 100% silicone, has chemicals like fungicides and solvents that can leach out over time in an aquarium. These can be highly toxic to fish and invertebrates.

Additionally, non-aquarium silicones are not designed for permanent water immersion. Seals can gradually weaken and decompose underwater. This leads to leaks or sudden tank failures down the road.

Buy Aquarium-Grade Silicone

Products like ASI Aquarium Sealant and Marineland Silicone Sealant are specially formulated for aquariums. They contain no harsh chemicals and are pH-neutral when cured. This prevents harming tank inhabitants.

The silicone polymers maintain their integrity and elasticity in wet conditions for decades. While pricier than hardware store silicone, it’s critical for aquarium safety.

In short, don’t gamble with unapproved caulks – always use silicone made for aquarium use.

Step-By-Step Silicone Re-Sealing Guide

Over years of use, silicone seals between glass panes can weaken and begin leaking. Fortunately, a full re-seal restores the tank integrity. Follow these steps:

1. Drain and Remove Components

Empty the tank and clean inside surfaces. Remove filters, heaters, etc cemented in place.

2. Cut Out Old Silicone

Use a razor blade to cut and scrape away all the old silicone down to the glass. Remove debris.

3. Dry Glass Panels

Allow glass to dry fully before re-applying silicone. Moisture weakens the bond strength.

4. Apply New Silicone

Run a fresh bead evenly along the seams, smoothing with a scraper.

5. Clamp Panes

Apply clamps along the silicone lines to hold glass tightly together as it cures.

6. Allow Full Cure

Give the silicone sealant at least 24-48 hours to cure fully before filling the tank.

7. Leak Test

Fill the tank partially and let sit for several days, checking closely for leaks before fully filling.

With the right silicone and technique, re-sealed tanks can last many years. Schedule re-seals before leaks start for best results.

Top Aquarium Glass Glue Product Recommendations

With all the different silicone and acrylic options on the market, here are some top-rated aquarium glass glue products to consider:

Aqueon Silicone Sealant – 100% silicone formula bonds glass and resists mildew. Easy nozzle dispensing.

ASI Silicone Sealant – Veterinarian-approved aquarium silicone. Flexible and waterproof when cured.

Marineland Silicone Sealant – Specifically designed for glass aquariums. Clear finish.

All-Glass Aquarium Sealant – Non-toxic silicone ideal for new or re-sealed tanks. Dependable quality.

AMAZING GOOP Marine Silicone Sealant – Bonds glass, acrylic, and plastics. Withstands wet conditions.

Weld-On #16 Acrylic Cement – Permanently bonds acrylic pieces together. For plastic tanks and decor.

Shop around to compare options and prices. Always verify that the product is intended specifically for aquarium applications before purchasing.

Troubleshooting Common Aquarium Glue Problems

Like any DIY project, things don’t always go according to plan when working with aquarium glue. Here are some potential problems and solutions:

Issue: Glue isn’t curing fully and remains tacky.

Fix: Ensure correct product for the material and sufficient cure time. Low temps or poor ventilation can inhibit curing.

Issue: White crusty deposits along silicone seams.

Fix: Cut away deposits with a plastic scraper. Ensure pH and water chemistry are balanced.

Issue: Secured decorations become unglued and fall over.

Fix: Use glue specially formulated for underwater use. Allow several days for it to fully cure before submerging.

Issue: Cloudy haze or areas in cured silicone.

Fix: Unfortunately, once cured there’s no fix. Re-apply new silicone for best clarity.


From securing glass panes to decorating with rocks and driftwood, the right aquarium glue is critical for building your underwater world. You can confidently tackle aquarium projects using specialized products designed specifically for glass and acrylic adhesion underwater. Just be sure to follow safety precautions during application and curing. Your fish and tank will thank you!