When shopping for a new aquarium you’re not likely to be surprised by the many glass designs available on the market. But did you know there is a plastic-based alternative that is very competitive with glass?
Acrylic aquariums have been popular in the hobby for decades. While acrylic is not glass (silicon dioxide) it is structurally a glass material (an amorphous solid) and being transparent, equally suitable for holding water!
But how do acrylic vs glass aquariums measure up to one another? Let’s get to know both and see which is the best fit for your next setup!
Benefits of Acrylic Aquariums
Here are a few of thee benefits of choosing and acrylic aquarium over glass:
Weight Savings
Acrylic aquariums are especially popular for large displays because they are so light. On average an acrylic tank weighs 50-60% as much as a glass aquarium of the same dimensions.
Anyone who has tried to move an aquarium larger than 30 gallons knows it takes at least two people to do so. Acrylic aquariums are perfect for spaces where weight matters (i.e. tabletop aquariums) and you don’t want to do any heavy lifting in the future. The lighter acrylic tank also means there’s that much less weight for the stand to deal with.
If you’re shopping for a new aquarium and need to know how much weight you’re dealing with this online calculator will tell you how much your glass or acrylic aquarium weighs.
Strength
While glass is more resistant to scratching acrylic is very resistant to impacts. A blow that would shatter a glass aquarium won’t have nearly as much impact on an acrylic one. And this is despite acrylic being thinner relative to a similarly sized glass tank!
Keep in mind that you may still see scratches or other signs of impact from a sharp blow. But at least there won’t be water and fish on the floor. THis makes acrylic aquariums particularly good for households with active children, large pets, or other hazards to a glass fish tank.
However, acrylic aquariums need stronger bracing along the bottom and top, especially with larger tanks. The weight and pressure of that much water can cause them to eventually bow and break if the aquarium top isn’t strongly reinforced.
Optics and Appearance
Since the plastic is lighter and simpler to mold, acrylic aquariums are much easier to shape into non-standard designs. And even when molded into curves, cylinders, etc, they don’t distort viewing of fish and coral the way glass aquariums would if curved. Glass is simply too rigid and heavy to mold into the more unusual shapes acrylic regularly takes.
Acrylic also has an almost identical index of refraction relative to water. This means light passing in and out of acrylic doesn’t bend nearly as much as it does when passing through glass, giving you an accurate view of the tank inhabitants!
Acrylic is also clearer than typical aquarium glass, which transmits roughly 83% of the light that passes through it. Due to the iron content it has a greenish hue that’s noticeable even in smaller aquariums.
Starfire (ultra-low iron) glass is superior optically, with over 90% light transmittance, making it on par with acrylic clarity-wise. However it is significantly more expensive and generally reserved for high-end displays. To save costs manufacturers sometimes use starfire glass on the front panel only, using normal glass on the sides and rear.
In order to properly clean the outside glass of an acrylic aquarium you need to use a brush that’s designed not to scratch the material. Standard magnetic and scrubbing pads not only scratch but leave places for algae and biofilms to collect, making the scratches even more obvious over time.
Benefits of Glass Aquariums
Here are a few of the benefits of glass aquariums:
Price
The first and most obvious difference between glass vs acrylic aquariums is the cost. Glass aquariums are 2 to 5 times cheaper than acrylic aquariums of a standard volume and design. This makes them perfect budget-wise for the vast majority of hobbyists as the advantages of acrylic simply aren’t worth the extra cost.
Glass aquariums are mostly mass-produced and are immensely popular. That means there is a lot less variance price-wise until you start moving beyond 125 gallons or want a non-standard design. Acrylic aquarium pricing depends on the volume, design, formula, and many other factors.
Durability
Unlike acrylic, which is easily scratched, glass is extremely hard and durable. It takes some real effort to scratch a glass aquarium. Falling live rock or other decorations are the usual culprits.
But being careless with a tool, a forgotten ring on your finger, and even the nibbling of toothy fish can leave visible marks on the aquarium. The hardness of glass prevents tank inhabitants and most abrasive cleaning agents like algae scrubbers from causing harm.
On the other hand, when it does happen, glass scratches are harder to remove than acrylic ones, which can be buffed out with sandpaper or filled with sealants. The only way to remove a serious scratch on glass is to replace the entire panel (or the aquarium).
Long-term Appearance
As an acrylic aquarium ages UV radiation can cause it to visibly yellow due to a photochemical reaction. Unfortunately, the process is irreversible, however many modern acrylic tanks have additives that prevent or at least slow this process.
Generally this is caused by direct sunlight, though you shouldn’t be placing an aquarium there anyway due to algae issues. But the UV output of high intensity coral lighting can also cause yellowing. On the other hand, glass aquariums maintain their clarity regardless of UV intensity.
Better Insulated
Placing your hand against a glass aquarium will allow you to confirm that your tank is radiating significant amounts of heat back out into the environment. If not for your heater the tank would have long since cooled.
However, acrylic aquariums lose heat 20% slower than glass does! This small but significant amount of insulation translates into 20% less power consumption by your heater and helps the stability of your aquatic environment.
Smaller tanks lose heat faster than larger ones do, making acrylic an excellent choice for nano reefs, which contain invertebrates especially sensitive to rapid fluctuations in water parameters, such as corals and anemones.
Summary
| Advantages | Acrylic | Glass |
| Weight | X | |
| Price | X | |
| Scratch-Resistance | X | |
| Rigidity | X | |
| Customization Potential | X | |
| Viewing (Clarity, Distortion) | X | |
| Aging (Yellowing over Time) | X |
When it comes to choosing between an acrylic vs glass aquarium there really is no cut and dry answer. Which material is best depends entirely on your needs as an aquarist. If budget is your primary concern, glass is the obvious choice once you go beyond 20 gallons.
Acrylic offers significant advantages in weight, impact resistance, and clarity. However glass is far more durable and won’t yellow over time with UV exposure. Both acrylic and glass are fantastic choices for your next aquarium!
