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How to Make a 3D Fish Aquarium Background

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Zach's writing ranges from matters of gardening, cooking, aquariums, and fish to more niche topics like coin collecting.

3D aquarium backgrounds are the latest trend.

3D aquarium backgrounds are the latest trend.

As trends in the aqua world progress forward, it's becoming apparent that bare tanks are no longer in. Heavily planted and biotope-themed tanks are a hot ticket at the moment, but custom 3D backgrounds have really stolen the show. The reason being is that these backgrounds provide a unique, three-dimensional aspect and can be tailored to work with any theme of aquarium. Having a custom aquarium background doesn't come without a little work though. So if you're up for the challenge, I'll show you how to make a fish tank background with Styrofoam and a few other simple materials. Take your tank to the next level.

Materials Needed

  • Empty Aquarium: Installing a background requires an empty fish tank. No fish, no water, no problem!
  • Styrofoam: As this is the main component of the background, you'll want to make sure that you get pieces large enough to fit against a wall in your aquarium. Larger sheets of Styrofoam can be purchased at home improvement or craft stores.
  • Aquarium Silicone: Silicone will effectively hold the background in position, so it doesn't float when the tank is filled with water. Not all silicone will work! Only get GE #1 silicone. This is 100% silicone with no mold or mildew prevention added to it. Any silicone with mold/mildew control will leach and kill aquarium fish! Silicone can be found at home improvement or pet stores.
  • Drylok Masonry Sealer: This masonry sealer is available at most home improvement stores. It is used for pond applications but is safe to use in the aquarium. (The smaller can sold in stores is plenty for the job and costs around $14.)
  • Quikrete Concrete Dye: Used in combination with the Drylok Sealer, the concrete dye will provide aquatic-safe color for your background.
  • Knife or Butane Torch: Got to have something to carve out your background.

To purchase the needed supplies, around $40–50 should be expected. I spent $45 and was able to build a background for a 30-gallon and a 10-gallon aquarium.

Do Your Homework

I can't even begin to stress how important this step is. Knowing tank dimensions and the desired shape, depth, and color of your future background will greatly ease troubles in the long run. If you're using a glass aquarium, keep in mind that the upper rim may need to be taken off for the background to fit in the tank properly. If the rim does need to be removed, do so with a razor blade and then silicone it back on when finished.

The possibilities are endless as you can create realistic rock walls, river stones, tree roots, and even waterfalls.

The possibilities are endless as you can create realistic rock walls, river stones, tree roots, and even waterfalls.

Carving the Styrofoam

Here's where you can let the artist in you run wild. All you'll have to do is cut your styrofoam to size and then begin carving. The possibilities are endless as you can create realistic rock walls, river stones, tree roots, and even waterfalls. Overall, it's your decision what to create, but keep in mind these tips that will help speed the process.

  • Torch over a Knife: While a knife can effectively create an aquarium background, the mess it creates from carving out the styrofoam can be overwhelming. A small butane torch can help! Instead of carving out and removing styrofoam to create texture, a butane torch will melt and cause the styrofoam to shrink, leaving no mess at all. If you do use a torch, be sure to create your styrofoam design outside, so you don't breathe in the fumes.
  • Thickness: Adding varying degrees of depth to your background enhances its realistic appeal. To add more depth to your background, try stacking the styrofoam sheets on top of each other. Use silicone between the sheets to seal them together, then begin carving.
  • Filter/Heater Awareness: Don't forget about these essential components! Filter tubes and heaters need to be taken into consideration so that your background doesn't inhibit their ability to function properly. Carefully plan out where these will be located or incorporate them into your design so that you don't run into problems when you put the tank together.
Examples of styrofoam carvings.

Examples of styrofoam carvings.

Another example.

Another example.

Color and Sealing

Hopefully, you've made it to this point with no setbacks! Progressing to color and sealing, you'll be glad to hear that they're both done in the same process.

  1. Pour some Drylok into a bowl or disposable container. Add very small amounts of concrete color to the sealer until you reach a color you like.
  2. Paint the entire background with a heavy coat. Cover all exposed styrofoam with the sealer/color mixture.
  3. For realistic color, add shadows and highlights with different shades of the sealer/color mixture after the first coat has been allowed to dry for one hour.
  4. Once you're satisfied with the color, allow the background to dry for three days! This drying time is recommended by the Drylok Sealer and should not be rushed. After three days of drying, the background will not leach any toxins and is completely safe for aquarium use.
  5. To secure the background to the aquarium, use dabs of silicone between the background and aquarium wall to lock it in place. Allow the silicone to dry completely! This will be a two-day wait.

Final Steps

Once the silicone holding the background to the aquarium has dried, you're ready to fill your tank! The process all in all takes around a week to complete, but the results are well worth it! You'll have compliments flying in with the sight of your new background. I hope that you've enjoyed my article on how to make a fish tank background. If you have any comments or questions, please leave them for me below. I'll try my best to respond promptly!

I'll leave you all with some pictures from my aquariums. Although I no longer have them, I can't help but be reminded of the good old fish days.

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© 2012 Zach


Rick Mcginnis on September 15, 2019:

Can i do a large background in two pieces?

Dave on February 15, 2019:

More of a question than a comment. I’m wanting to make my own 3-D backgrounds for my 10 aquariums and I’m wanting to know what is the best styrofoam to use?

Zach (author) from Colorado on July 10, 2013:

Zach - I used the Quikrete brand with great results.

zach on July 08, 2013:

what brand of concrete dye is safe?

Brandy on December 19, 2012:

I have my styro carved. I'm trying to decide what color to use to tint the drylok. My 55 gallon tank will have white pool sand with some large rocks that match the sand. Do you have pictures of the different colors you can use to tint the drylok?

Zach (author) from Colorado on January 23, 2012:

MonetteforJack - There's always room for one more fish tank, right? Ha. Glad you enjoyed.

TropiCoaqua - I would love to see your finished background! Good luck on your project.

Amar Salvi from India on January 19, 2012:

Cool stuff,Joe. This is something I haven't tried and wanted to. Thanks.Will send you a pic when I do my first one:-

MonetteforJack from Tuckerton, NJ on January 17, 2012:

Oh! I wish you did this hub a year ago! :) Very informative and interesting, specially to my husband whose hobby is taking care of his fish tanks.

Zach (author) from Colorado on January 12, 2012:

Danette Watt - I love your question, as it answers itself! Yes, without the Drylok, I would imagine that the Styrfoam would become a mess.

Danette Watt from Illinois on January 11, 2012:

Doesn't the styrofoam start falling apart? Or does the paint prevent that? Never mind, I guess that's why they call it "Drylok"! What an interesting project.

Zach (author) from Colorado on January 11, 2012:

learnlovelive - Hey thanks for the feedback. You two should really get to making one. In all reality, if she knows all that, you're more set to go than I ever was. Thanks for reading and good luck to you!

mariekbloch - I appreciate the feedback. I sure hope the fish liked it! The cave on the 30 gallon tank was Dom's(the pictured fish) favorite hangout spot.

mariekbloch on January 10, 2012:

Very cool and informative. It looks great. I'm sure the fish appreciate it too. One less invisable wall for them to bump into.

learnlovelive from U.S. on January 10, 2012:

Excellent job. This is a really cool project that I would like to try some day. My girlfriend really enjoys painting, textured mediums, and mixed media art so I feel this would be extremely fun to do! Nice use of affiliate strategy as well. Up and awesome!

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