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How to Build a DIY Aquarium in 15 Easy Steps (With Pictures)

Lindsey Stanton Profile Picture

By Lindsey Stanton


Have you found yourself frustrated with the aquariums available on the market? There are only so many shapes and sizes that are widely available and finding anything different can be difficult and custom-built aquariums can be hundreds to thousands of dollars. If you’ve found yourself frustrated on the aquarium front, there’s good news for you!

You can build your own aquarium from scratch for far less than what a custom aquarium will cost you. If you have the ability and knowledge to cut your own glass, you can save even more. Building a DIY aquarium isn’t easy and is a time-consuming task, but it can be fun in the process and rewarding when it’s finished. There might not be anything more satisfying than relaxing in your home while looking at your aquarium you built yourself.

aquarium plant divider

Benefits of Building a DIY Aquarium

The biggest benefit of building your own aquarium is the ability to customize the aquarium in every way. Not only are you able to choose every piece of equipment according to your preferences and needs, but you can also choose the exact size and shape of your tank. This allows you to create a completely custom aquarium to fit with your design preferences and available space.

Aquarium-grade glass
Image Credit: Andrzej Rostek, Shutterstock
Supplies You’ll Need
  • Aquarium-grade glass
  • Glass cutting equipment (optional)
  • 100% silicone
  • Low-grit sandpaper
  • Clean cloth
  • Rubbing alcohol
  • Disposable gloves (optional)
  • Masking or painter’s tape
  • Square
  • Aquarium equipment of your choosing
  • Aquarium rim or brace OR supplies to build one (optional)
  • Flat, clean work surface

aquarium plant dividerThe 15 Steps to Build a DIY Aquarium

1. Make a plan

The old adage “measure twice, cut once” is definitely at play here! You don’t want to miscut your glass or provide the wrong measurements to whoever is cutting the glass for you. Plan every piece of your tank before you even purchase supplies. You will save money and time by being prepared.

Measuring Glass Aquarium
Image Credit: Andrzej Rostek, Shutterstock

2. Buy your supplies

Take a thorough list with you to the store and include all of your measurements. This will help ensure you don’t forget anything important and that you get the correct sizes and shapes of everything needed.

3. Prep your workspace

When building a DIY aquarium, you want to make sure to have a flat surface that is clean and soft enough to protect the glass, but not so soft that the tank will sink into the surface as you’re trying to build. An outdoor rug or something similar on a concrete, wood, or tile floor should work well for this. You’ll also want a space that is clean and free of debris. Otherwise, you may end up with leaves, pet hair, or trash stuck in the silicone of your new tank.

Measuring Cutting Glass
Image Credit: Andrzej Rostek, Shutterstock

4. Purchase or cut your glass

Once you’ve come up with a plan, it’s time to pick the glass. Depending on the size of the tank you’re building, you’ll want glass that is a minimum of 4mm thick but ideally is 5-6mm or more. If you are comfortable cutting glass or have old glass you can practice on, then purchasing uncut pieces of glass will save you money. Many people are not comfortable or equipped to cut glass, in which case you will be able to purchase custom-cut glass from hardware or aquarium stores.

5. Sand the edges

Sand all of the raw edges of the glass. Cut glass often has uneven, sharp edges that can easily cause injury and will also make it extremely difficult to get a good seal on your tank.

Sanding Glass Edge
Image Credit: John Danow, Shutterstock

6. Wipe it down

Wipe the glass down with the rubbing alcohol and soft cloth. This will remove oils from your skin that may have gotten onto the glass, as well as removing dirt or small glass shards.

7. Place the tape

Place the tape sticky side up underneath the piece of glass that will become the aquarium base. Leave tape tabs at each tape spot since this tape will help to hold your glass in the correct position as the silicone cures.

Sticky tape, scotch tape
Image Credit: augustos, Shutterstock

8. Set up the glass

Lay all the aquarium glass out in the location where it will be installed. This should look like an aquarium that has had all the seams cut, so all of the glass is lying flat on the work surface.

9. Lay the silicone

While you don’t need aquarium-specific silicone, you do need to make sure you get 100% silicone that does not have any mold or mildew prevention or other additives. Silicone comes in squeeze tubes, like toothpaste, and in canisters that fit into a caulk gun. Choose whichever you are more comfortable working with. Silicone can be inexpensive, so you should be able to practice before you start applying silicone to the glass.

You’ll want to apply the silicone in a strip down the edge of your first piece of glass, then set it into place. Make sure all edges line up and then smooth the silicone down with your finger. You can wear a glove for this if you prefer. Work quickly because the silicone will start to cure and thicken quickly after application.

Applying Silicone On Glass
Image Credit: noprati somchit, Shutterstock

10. Use the square

Once you have the first aquarium corner installed, use the square to make sure the corners and sides are even and in the correct place. Once you’ve ensured all the sides are in the correct spot and are level, flip up the tape tabs to help hold the glass pieces in place.

11. Place the brace

If you are building a small tank, you can skip this step. Most tanks over 20 gallons will need a brace or a rim. This piece helps ensure the pressure of the water inside of the tank doesn’t push out against the silicone seal too much, damaging it. The brace can be a piece of cut glass that is put into place between the two long sides of the tank and sealed into place with silicone. You can also purchase or build an aquarium rim with a built-in brace.

12. Cure the silicone

Once your aquarium sides are on and your brace is in place, if applicable, leave the tank where it is while the silicone cures. If you don’t want to undo much of the hard work you’ve already done, don’t move the tank. Silicone can take anywhere from 24-72 hours or longer to cure depending on environmental variables. Usually, silicone will be fully cured in 48-72 hours.

Empty Aquarium
Image Credit: YUS images, Shutterstockwwwww

13. Test the tank

Once you are sure the silicone has cured, you can test the tank to ensure it is water fast. The best way to do this is by filling the tank partway with water, about ¼ to ½ of the tank will suffice. Watch the seams of the tank as you do this so you can catch leaks quickly. If you don’t spot any leaks, leave the tank for a couple of hours, and check again. If you still don’t see evidence of leaks, fill the tank all the way up and leave it for 12 hours or longer to ensure it does not leak.

14. Drain the water

Once you’re certain your tank is free of leaks, drain the water from it. Attempting to move the tank, no matter how small, while it is full of water is risking damage to the silicone seals. That’s not to mention the risk of dropping or otherwise damaging the tank.

Moving water waves and bubbles bursting in the aquarium
Image Credit: boomkee2532, Shutterstock

15. Set things up

Get the tank to the location you want it to go before you start adding substrate, décor, plants, and water. Set up any filters, air stones and pumps, or other equipment you’ve chosen for your new tank. Once the tank is up and running, you’re ready to add fish!

aquarium plant divider


Building a DIY aquarium isn’t a project that you will be able to complete in a day or two, so be prepared to dedicate a significant amount of time to planning, building, and setting up your new tank. If you go into the project well prepared and with a solid plan in mind, then you might find this project an enjoyable use of your time.

If you’re new to this type of project, then you might want to start with a simple aquarium design. As you become more comfortable with these skills, you’ll be able to build more complex DIY aquariums. Take it slow and easy, be prepared, and dedicate time to building your DIY aquarium and you’ll be rewarded with a beautiful aquarium that is exclusively yours.

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Featured image Credit: Chaikom, Shutterstock

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