How to Build an Aquarium Background

Updated April 17, 2017

One of the greatest pleasures of the aquarium or fish-keeping hobby is building a dramatic background for your show tank. For the beginner, the background makes the fish stand out and can complement the room's decor and reflect personal preferences. For the more experienced aquarist, creating an authentic biotope will replicate the natural habitat of the fish and highlight their unique behaviour. The aquarium background can be simple, economical and low maintenance or as elaborate as you wish.

Choose the type of fish you would like to keep in the aquarium, whether freshwater or saltwater. Decide on either a naturalistic or artistic theme. The background for an aquarium in a children's playroom will be very different from one built to highlight the unique behaviour of, say, Tanganyika cichlids. If a natural biotope is your choice, research the preferences of your fish for rocks, plants and caves.

A design-driven theme can coordinate with decorating or hobbies. The family that wants a "SpongeBob" aquarium will certainly not care about the correct natural setting for the fish as much as a colourful design. Be sure to choose low aggression community fish for the casual aquarium.

Buy an aquarium mural at your pet store for the easiest background installation. This is a plastic sheet, usually a roll sold by length. A variety of mural designs ranging from realistic underwater scenes to fantasy subjects, some in 3-D, are available. If the aquarium will house marine fish, but you are not bothering with live rock or coral, you can still get the coral reef effect in a mural. Solid colours such as blue, green or black are also offered and are the most popular.

Measure the height of your aquarium, as the rolls come in different widths. Trim the sheet with scissors to the exact dimensions of the side of your tank that faces the wall. Attach the background to the outside of the tank with clear tape.

Buy plants for a beautiful and healthy background for plant-loving fish. Use tall varieties of aquatic plants planted in pots or in the aquarium gravel substrate. Avoid fish that uproot plants such as most African cichlids. Of course, for the look of plants without the maintenance, plastic plants are indestructible and widely available.

Choose tall Amazon sword plants for a South American biotope for angelfish, discus, rams and similar fish. Real plants can be combined with a purchased mural background in a single colour like blue or one printed with pictures of a plant aquascape. South American fish also enjoy the addition of pretreated wood or even large dramatic branches to the background. The use of wood helps to maintain the acidic pH these fish enjoy and gives them some relief from stress by providing hiding places. Purchase the wood where aquarium supplies are sold. For tanks over 200 litres (45 gallons), you may wish to order custom-sized branches from an Internet supplier.

Build a dramatic rock wall to encourage breeding behaviour and give African cichlids and other aggressive species a rest. Secret brooders such as Julidochromis use caves to reproduce, and most of the African mouth brooders benefit from some seclusion to reduce stress. In peaceful community tanks that contain live bearers like mollies and sword tails, rock walls, towers and caves are completely unnecessary, but a few rock structures will provide interest.

Build rock walls by hand out of lava rock or other natural stone. Build carefully, placing larger rocks directly on the bottom of the tank--not on the gravel. Another approach is to glue rocks to a "trellis." Build these structures using fish-safe epoxy and a plastic framework. Pieces of plastic milk crates or similar storage containers from an office supply store can be cut apart and used to frame the "walls." Weight the structure with bottom rocks that are larger and heavier for stability.

Use an aquarium insert if your budget allows. Most inserts are moulded plastic designs available via the Internet that can be custom produced for your aquarium or bought and cut down to fit your tank. Inserts can incorporate overhangs and realistic looking rock walls and caves. Although expensive, inserts are easier to keep clean than structures made from natural rock, and most of the work is already done for you.

Purchase rock caves from an aquarium retailer or larger pet store for a no-build background. These rocks already have holes in them that provide places for fish to hide and breed. Two or three large rock structures positioned far enough from the back wall to allow for cleaning will give a dramatic look and provide useful cover. Remember the rule of thumb to allow 18 litres per 5 cm (2 gallons per inch) of fish for grow-out in freshwater aquariums. For saltwater, the rule is roughly 18 to 22.5 litres (4 or 5 gallons) per 2.5 cm (1 inch) of fish stocked. Rocks displace water, so be sure to calculate the volume remaining after you have decorated, then add the right amount of fish.

Use live rock for a natural saltwater habitat. This is rock from the ocean that is already inhabited by marine life. Live rock by itself becomes a fantastic background that grows real, living sea creatures including corals, sponges and invertebrates. Live rock takes weeks or even months to establish before you should introduce fish and is for the truly dedicated. If you are new to saltwater, your aquarium supplier will be able to advise you based on the size of your tank and your goals.

The beautiful saltwater tanks you see in restaurants or public places usually avoid live rock and live corals for lower maintenance. Plastic roll murals in plain colours or coral prints and the addition of pieces of (dead, clean) coral are the usual choices.


Choose backgrounds that contrast with fish colours. Keep backgrounds simple in smaller tanks. Don't overcrowd the tank; keep the water-to-fish ratio in mind.


Watch the weight of added rocks; lava rock is the lightest. Make sure rock structures are stable. Falling rocks can injure fish. Be sure in-tank background elements can be removed for cleaning. Use noncorrosive, water-safe decorating materials.

Things You'll Need

  • Plastic background mural sheet
  • Lava or other natural rocks
  • Plastic rocks and rock towers
  • Moulded plastic insert
  • Epoxy
  • Aquatic plants
  • Live rock and live coral
  • Decorative coral pieces
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About the Author

In her career, Maryann Kay has transitioned from advertising writer to corporate financial/consumer vice president on billion-dollar businesses. Along the way, she mastered entrepreneurship consulting, wine importing/travel and real estate businesses. A frequent speaker, writer and financial, travel and home care blogger, Kay's writing has appeared in national publications such as the "New York Times," "Wall Street Journal" and "Advertising Age."