How to Build an Artificial Rock Aquarium

Written by naomi bolton Google
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How to Build an Artificial Rock Aquarium
Most fish live in an environment filled with other life and structures important to their habitat. (champignons aquarium image by Francis Lempérière from

Fish and other underwater creatures live surrounded by rocks and plant life, in an environment of structural complexity. Each part of this habitat is important to the different animals found underwater. Fish hobbyists therefore tend to replicate as many aspects of the natural environment as possible. Rocks make for natural hiding places, but natural rocks are heavy and displace their weight in water. For these reasons, artificial rock is the ideal medium to use. By creating the artificial rock yourself, you will ensure that the finished product is exactly what you had in mind. The following will allow you to create an artificial rock background for a 150cm by 55cm aquarium.

Skill level:

Things you need

  • 2 pieces of polystyrene, 59 inch by 21.65 inch each
  • 8 to 10 fist-sized pieces of polystyrene
  • 1 tube of nontoxic aquarium silicon
  • Sharp carpet knife
  • Heat gun
  • Concrete, 4.99 Kilogram
  • Concrete colour, 1 cup
  • Gloves
  • Mist bottle
  • Paint brush
  • Cloth
  • Salt, 1.22 Kilogram

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  1. 1

    Glue the two pieces of large polystyrene together, back to back, with nontoxic 100 per cent aquarium silicon. Glue the eight to 10 fist-sized pieces of polystyrene to the existing double-thick piece of polystyrene so as to form small raised areas.

  2. 2

    Hack the large sheet to create holes and ravines, and shape the fist-sized pieces of polystyrene to resemble rocks.

  3. 3

    Use the heat gun to melt and smooth the entire polystyrene sheet, including the raised rock features.

  4. 4

    Mix up the 5kg batch of concrete. Add the colour slowly until you have the desired shade. Using gloves, smear sufficient concrete to allow you to cover the entire front "face" of the polystyrene background with a thin layer.

  5. 5

    Leave the concrete-covered background to dry for 48 hours.

  6. 6

    Use the paint brush to splash the remainder of the concrete colour onto the background. Spray a sufficient mist from the bottle so that the colours begin to run.

  7. 7

    Use the cloth to rub the colour onto the background to imitate the appearance of natural rock and leave the background to dry for 48 hours.

  8. 8

    Soak the background in a solution of 249gr salt to 2.6 gallons warm water and leave overnight. Repeat the process three more times, using a fresh salt solution each time. The artificial rock work can now go into your aquarium.

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