During my 30 years of fishkeeping, this is a question I am asked a lot:
Which is better, a glass or acrylic fish tank?
I can understand why this question comes up so often…
Both glass and acrylic, a clear plastic, are commonly used in fish tanks. At first glance, there is not much difference between the two – both are clear and capable of holding large amounts of water.
It’s not until you actually own each type of aquarium that the differences become obvious.
Over the years, I have owned many different aquariums. Some were glass while others were acrylic.
While I prefer glass, I won’t argue that there are certain circumstances where acrylic is better – I’ll get to that in just a moment.
So read on to discover the pros and cons of acrylic and glass and find out which is right for you.
But first, for those of you who do not want to get bogged down in the technical details…
If you are new to the hobby and just want a quick recommendation on which is best for you – glass is the way to go.
I recommend glass aquariums for beginners who want a tank less than 150 gallons (568 liters).
And the reason for this is simple…
As I covered in my beginner’s guide to choosing a fish tank – incredible care must be taken with acrylic tanks to avoid scratching, especially during cleaning.
It’s hard to appreciate how good your fish look when you are staring through a scratched tank.
Not to mention that glass aquariums are easier on your wallet!
These two points make glass aquariums more suitable to beginners than acrylic ones.
That said, acrylic does have its benefits, namely being lighter, which makes it more suitable for large tanks – tanks so big that most beginners wouldn’t even consider them.
The difference between glass and acrylic aquariums
As you see in the table below, glass and acrylic are very different materials, each with advantages and disadvantages.
Don’t worry if this table doesn’t mean much to you, I will cover each point in greater detail later in the guide.
|Yellows with age
Now that you have read the summary, let’s take a closer look at the differences between glass and acrylic aquariums.
This one always comes as a surprise, but glass aquariums are usually cheaper than acrylic.
I know, I know…. Acrylic as a material is cheaper to manufacture and transport than glass. But a complete glass aquarium is still cheaper than an acrylic one.
And the reason for this is simple…
Glass aquariums are more popular.
Because of this, more glass aquariums are manufactured, which reduces the total cost.
However, there is a tipping point when acrylic aquariums become cheaper than glass aquariums. If you are shopping for a particularly large aquarium, around 150 gallons (568 liters) or larger, an acrylic aquarium is cheaper.
This is because glass weighs more than acrylic and is cheaper to transport.
And that brings me to my next point…
This is the main reason why I recommend glass, especially to beginners. Acrylic scratches waaaaaaay too easily.
My last acrylic aquarium was actually scratched during transport. Despite all the protective packaging, when I unboxed my new aquarium, it had a noticeable scratch down the left side.
But let’s say that your acrylic aquarium arrives safe and scratch-free. Anything brushing against the tank can scratch it. Yep, even just walking by your tank and making slight contact can rough up the surface.
If you have young children that constantly touch or play near your tank, or even a curious cat, steer clear of acrylic.
Even critters living inside your tank can scratch the surface. The sharp shell from a snail or sharp tooth from a fish is all it takes.
And when cleaning, you need to use an acrylic-safe algae scrubber. And good luck if you accidentally get a small piece of gravel or sand caught in it – it’s a one-way ticket to scratch city.
There are acrylic polishing kits that can be used to restore acrylic tanks to their former glory, removing all signs of scratches. But do you really need more chores? And besides, you will have to drain your aquarium to remove any scratches from the inside.
Glass, on the hand, is much more difficult to scratch, that’s why it makes such a great material for the windows in your home – it is difficult to accidentally scratch glass!
Acrylic aquariums look “beat up” much quicker than glass aquariums.
I don’t need to tell you that glass is heavier than acrylic. But just how much heavier glass is may surprise you.
Imagine you have two aquariums that are the exact same size. The only difference between the two is that one is made from acrylic and the other from glass.
The glass aquarium can be as much as 10 times as heavy as the acrylic aquarium.
The lighter weight of acrylic has advantages.
A small acrylic aquarium is much easier to lift than a glass one. You can easily move the tank around your home, even with water inside.
And when it comes to large custom-made tanks, you will need to consider the amount of weight that the floor in your home can support. Choosing acrylic over glass is a commonly used method of reducing the overall weight of the tank.
The hard, brittle nature of glass makes it difficult to shape. This is why most glass fish tanks are square or rectangular.
Curved glass aquariums have the added problem that it “bends light,” which makes the fish on the inside appear larger or smaller than they actually are.
Acrylic, on the other hand, is easily molded into any shape that you can imagine. It also bends light less, which means that your fish look how they should.
Okay, so this one is only relevant in the event of an accident. I don’t need to tell you to prevent heavy objects from crashing into your aquarium!
Acrylic is much more resistant to impacts than glass, which can break or chip.
But if bumps and crashes are a concern, you are better off choosing a different location for your fish tank.
The glass windows in your home are designed to let light in.
But this light can damage acrylic, causing it to become yellow and brittle over time.
UV light to be specific. If sunlight hits your aquarium (it shouldn’t) or if you have UV aquarium lights to help with plant growth – it will eventually wear down the acrylic.
While there are “UV-resistant” acrylic aquariums, even these eventually discolor.
Every acrylic aquarium I have ever owned has reached the stage where it becomes cloudy. And while the process may have taken years, it seems like it is unavoidable.
Glass, on the other hand, does not suffer from the same problem and will remain clear, no matter how much light shines through.
If you love DIY projects and want an aquarium that is easily modifiable, acrylic is the way to go.
You can easily drill holes in acrylic to make way for pump outlets, overflows or anything else your creative mind can think up.
While you can still drill through glass, as long as it isn’t tempered, it is a nerve-racking experience and requires much more care than drilling into an acrylic tank.
As you see, the pros and cons of each material heavily impacts how you can use your aquarium.
If you want an unusual-shaped aquarium or plan on modifying your tank with a drill, acrylic is the way to go.
But again, for the vast majority of you, it’s hard to beat a good glass aquarium. With proper care, a glass aquarium will outlast you!
What type of aquarium do you prefer? Let me know in the comments below
Ian Sterling, founder of Fishlab.com, began his aquarium journey over 30 years ago, driven by a deep fascination for fish and their diverse personalities. His website, Fishlab.com, is dedicated to making fishkeeping accessible and enjoyable, offering beginner-friendly guidance, expert insights, and a community for aquarists to connect and share experiences.