Hot glue is aquarium-safe as it doesn’t release any harmful chemicals. It’s also non-toxic to tank inhabitants as it decomposes when wet or moist. You can use hot glue to fix various aquarium objects. However, the glued objects should be placed in the aquarium only after the glue has cooled down.
Let’s now learn more about how safe it’s to use hot glue in aquariums.
What Makes Hot Glue Aquarium-Safe?
Hot glue is safe for aquariums as it decomposes fully when moist or wet.
It’s also non-toxic to fish as it doesn’t leach any harmful chemicals.
When used from a glue gun for bonding aquarium objects, hot glue doesn’t alter the water parameters inside the aquarium.
Since hot glue is waterproof, it’s widely used by aquarists to glue numerous aquarium objects.
Also, hot glue is similar to plastic that hardens over time.
So when used in aquariums for bonding objects, it becomes similar to any other plastic object placed in the aquarium.
Some people argue that hot glue releases fumes when exposed to water. It’s true that hot glue releases fumes if it’s overheated.
However, hot glue is entirely safe and doesn’t release any fumes if you put the glued objects in the aquarium after it has cooled down completely.
Also, the toxic vapors emitted by hot glue are generally of low concentrations and are unlikely to cause any significant issues to the tank inhabitants.
However, it’s always advisable to place the glued objects in the aquarium once the hot glue has completely cooled down to avoid any mishaps.
When used correctly and at the recommended temperatures, hot glue sticks aren’t toxic nor release fumes.
While hot glue is safe for aquariums, it must be noted that it’s not primarily designed for aquarium use.
Many aquarists use hot glue as a quick fix instead of looking at it as a permanent solution to their aquarium problems.
Advantages Of Hot Glue

Hot-melt adhesive (HMA), also known as hot glue, is a form of thermoplastic adhesive.
It’s commonly sold as solid cylindrical sticks.
These sticks are heated at the appropriate temperature with a hot glue gun so that the liquid hot glue comes out of the nozzle while gluing things together.
The heat melts the glue. As the glue cools down, it turns back into solid form. This creates a solid bond between the objects.
Hot glue provides several advantages described below over solvent-based adhesives.
- When hot glue is cooled to a temperature below its melting point, it produces a strong bond that’s guaranteed to last for long.
- You can use it on porous as well as on non-porous surfaces. Due to its high viscosity, hot glue bonds uneven surfaces and fill gaps.
- Also, hot glue dries instantly once applied to a surface, unlike other silicone sealants that take some minutes to bond the surfaces together.
- The most significant benefit of hot glue is that it fixes almost anything immediately. It’s also non-messy as it doesn’t leave behind any residue after use.
- Apart from fixing aquarium decorations, hot glue is also beneficial for fixing cracks and leakages in the aquarium.
- Hot glue also has a long shelf life and can be disposed of without any special precautions.
Although hot glue has many benefits, it has some disadvantages as well.
Disadvantages of Hot Glue
Hot glue needs to be used with caution. You need to heat hot glue at an appropriate temperature for it to be non-hazardous.
Given below are the disadvantages of using hot glue:
- If hot glue is overheated, it’s poisonous. Overheating also causes a chemical breakdown in the glue, resulting in irritating or hazardous fumes.
- Another drawback of hot glue is that it’s toxic if you pour it directly into the water. Pouring directly into the water will result in the emission of toxic fumes.
- Although you can use hot glue underwater, it’s not the best option. When exposed to water, hot glue contracts more than its sticky form. This results in small seams or cracks in the hot glued joints.
Is Hot Glue Safe For Aquarium Plants?
Hot glue is not safe for live aquarium plants because it needs heat to melt, which is fatal for live aquarium plants. However, you can safely use hot glue to bond artificial aquarium plants.
Live aquarium plants perish due to the heat damage in the bonded areas.
So, it’s better to avoid using hot glue on live aquarium plants.
Is Hot Glue Safe For Aquarium Decorations?
Hot glue is safe for gluing aquarium decorations such as rocks, stones, and wood. The only thing to remember is to clean the rocks and stones before applying hot glue to them.
Aquarists often use rocks and stones to enhance the aquarium’s beauty.
A beautiful structure can be created by gluing rocks of different shapes, sizes, and colors.
Here, hot glue can bind the rocks and stones together and maintain their natural beauty.
Also, you can use hot glue on aquarium driftwood.
You just need to ensure that the driftwood is clean of debris and dirt before applying glue.
Otherwise, the hot glue will not bond properly, leading to an unstable bond.
You can also use hot glue on ceramics and acrylics.
However, you shouldn’t exert too much pressure while using hot glue on acrylics to avoid damage.
Is Hot Glue Safe For Aquarium Substrate?
Hot glue is not safe as an adhesive for aquarium substrates such as sand and gravel.
Hot glue sticks to the sand or gravel and easily clog the aquarium.
This will cause problems with water circulation and filtration.
The tank inhabitants also suffer if the water gets contaminated due to inefficient filtration.
Related Questions
How long does hot glue take to dry?
Hot glue takes around a minute to dry when heated at a low-heat setting of a glue gun.
How long does hot glue hold?
Hot glue holds permanently if used on clean and dry surfaces.
However, it loses its grip and doesn’t hold for long if used on dirty and wet surfaces.
How long does hot glue take to cure?
Hot glue takes more than 12 hours to a day to cure completely.
So if you fix any aquarium decorations with hot glue, you need to wait for a day before placing the objects back in the aquarium.