Plywood Aquariums: Everything You Need To Know!

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Ever heard of an aquarium made of wood? Sounds crazy right? In fact, plywood aquariums have been popular in the hobby for decades. Aquariums made of plywood are strong, economical to build, and long-lasting, providing they are built properly.

First things first, let us have a look at exactly ‘what is a plywood aquarium’? A plywood aquarium is essentially a box, made from plywood which usually has a glass or acrylic viewing panel at the front. The plywood aquarium is then sealed with either an epoxy resin or rubber paint to make it watertight.

Plywood aquariums have been extremely popular amongst the monster fish-keeping community for many years. The beauty of a plywood aquarium is that it becomes very economical to build once you start to get to larger sizes.

You wouldn’t usually bother to build a 50-gallon plywood aquarium as it would be cheaper to buy a glass or acrylic one. However, if you wanted a 550-gallon aquarium, plywood may be a more economical option.

Are Plywood Aquariums Safe?

If you have been in the hobby for more than 5 minutes you will no doubt have heard stories of people’s glass fish tanks leaking. You may have also heard stories of acrylic aquariums failing and an entire side blowing off.

Have you ever heard of a plywood aquarium failing? Probably not! Providing they are built properly, plywood aquariums can easily last for 20 years or more without leaking or failing. Even after such a long period, a well-constructed plywood aquarium may just need draining down, re-coating with epoxy, then it is good for another 20 years.

Plywood aquariums are very safe due to the nature of their construction. Plywood aquariums are usually built from ¾” (18mm) plywood and sometimes from 1” (25mm) plywood. Plywood of this thickness is incredibly strong.

Much stronger than a glass of a similar thickness. Plywood aquariums usually have their seams reinforced with fiberglass which only adds to their strength.

If you are considering building a plywood aquarium, let us have a look at some of the basics, then I will go through the main pros and cons of a plywoods aquarium.

What Type Of Plywood Should You Use For A Plywood Aquarium?

I recommend using at least ¾” (18mm) thick plywood for a plywood aquarium. 1” (25mm) plywood is even better and should certainly be considered for a very large plywood aquarium.

Furniture grade plywood (sometimes called cabinet grade plywood) will have a nicer finish to it and is worth the extra cost if your aquarium is to be located somewhere where friends and family will see it.

When I have built plywood aquariums in the past, I have used ‘exterior grade’ plywood when it is available. Exterior grade plywood has better resistance to moisture, so if you do end up with some exposed areas, they won’t be affected by occasional water splashes.

The plywood provides strength to the plywood aquarium. Although thinner (and therefore cheaper) sheets of plywood are available, don’t be tempted to scrimp at this stage.

When your plywood aquarium is full of water, the outward pressure will be high and you don’t want the walls of your plywood aquarium flexing and potentially giving way.

How Do You Waterproof A Plywood Aquarium?

Clearly, the plywood itself isn’t water-tight. A plywood box filled with water will leak instantly, and over time the water will destroy the plywood.

To waterproof a plywood aquarium, the interior needs to be painted with either a 2-part epoxy paint or liquid rubber paint. There are various different products on the market to make a plywood aquarium watertight and each has its own advantages and disadvantages.

Does A Plywood Aquarium Need To Be Reinforced With Fiberglass?

It is not essential to reinforce the corners of plywood aquariums with fiberglass, however, it is probably best practice. I have built plywood aquariums both with and without using fiberglass.

The larger the aquarium, the more advisable it is to include fiberglass. If you find yourself building a plywood aquarium with a join in the timber (for instance if the aquarium is longer or wider than a single sheet of plywood), fiberglassing the joints is a must.

When fiberglassing, make sure you get every single bubble out of the fiberglass before it dries. Bubbles may pop under the pressure of the water, causing your corners or joints to leak.

How Much Do Plywood Aquariums Cost To Build?

Plywood aquariums usually cost somewhere between $1.50 and $2.00 per gallon to build, although this cost generally comes down to the larger the aquarium gets. A 300-gallon tank would probably cost in the region of $500-$600 whereas a 3000-gallon tank might be around $3,500.

A major advantage of building a plywood aquarium is that you can often get some of the supplies for free. If you visit construction sites you may find they have offcuts of plywood that are being discarded.

If you look in dumpsters on construction sites you will be amazed at what you can find. I recently constructed a 150-gallon plywood aquarium for less than $50. Every component of the build except the epoxy coating was free!

Plywood Aquariums – The Pros And Cons!

Advantages of Plywood Aquariums:

  • Generally cheaper to build than glass or acrylic
  • Easy to construct
  • Only basic tools are required to build
  • Any size or shape can be constructed
  • Highly customizable
  • Can be painted internally and externally
  • Long lasting

Of the many advantages to building plywood aquariums. Probably the biggest plus point for a plywood aquarium is the dollar-to-gallon ratio. As mentioned previously, you can usually build plywood for somewhere between $1.50 and $2.00 per gallon. The cost usually comes down to the larger the aquarium gets.

Ease of construction is another thing that makes plywood aquariums so attractive. Providing you have some basic DIY skills you can put a plywood aquarium together.

The main skills required when building a plywood aquarium are the ability to measure accurately using tape and cutting straight with a saw. Whilst you can use a hand saw, spending a few dollars on a basic power saw will be well worth the investment.

If you are looking for an aquarium that is anything other than rectangular, plywood may be the answer again. In theory, a plywood aquarium can be built to fit any shape. Plywood aquariums have been built to fit in corners, around structural columns, or even in ‘L’ shapes. If you can imagine it, you can probably build it out of plywood.

As well as being able to be built to any size or shape, plywood aquariums are also extremely customizable. You can drill them for overflows or make shallow areas or even add multiple viewing windows.

Another benefit of a plywood aquarium is that it can be painted to match a room. Externally, almost any paint can be applied, meaning you can really personalize your plywood aquarium, or simply make it match your decor.

Whilst most plywood aquarium builders choose for the inside of their aquarium to be the standard blue or black, a lot of the epoxy resins used to seal a plywood aquarium can be tinted, meaning you can paint them almost any color you want. If you have always wanted a bright orange aquarium, plywood may be for you!

A well-constructed plywood aquarium should last for about 20 years and frequently last even longer. Unlike a glass aquarium, which has a shelf life of around 10 years due to silicone sealant degradation, plywood aquariums are a real long-term prospect.

Disadvantages of Plywood Aquariums

  • They can look less attractive than a glass aquarium
  • Viewing of the fish is often just on one side
  • If they do leak, it can be hard to locate where they are leaking from

A major downside to a plywood aquarium is that your carpentry skill level determines how good they look.

If you are looking to build a plywood aquarium that will live in your house, you will want to be fairly good at carpentry, otherwise, your plywood aquarium may look a bit rough-and-ready!

Some people also consider the fact you can usually only view fish in a plywood aquarium through a single viewing window as a downside. Personally, I have never found this an issue. As plywood tanks are usually very large, the viewing window is normally large enough to allow you to view the whole aquarium.

Final Thoughts On Plywood Aquariums

Plywood aquariums have been popular amongst a small part of the fishkeeping community for decades. If you want to keep monster fish, you will need a monster tank and unless you have money to throw around, a plywood aquarium is probably the best to go.

If you are considering building your own plywood aquarium, the number one golden rule is to take your time! You will hopefully be enjoying your plywood aquarium for the next 20 years.

Taking a few extra weeks to make sure you build it correctly will more than pay off in the coming years.

About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James

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