How to Make a Cave From PVC Pipe

If you're looking for an inexpensive way to dress up your aquarium, consider PVC caves. PVC pipes are good cave materials because they do not rust or release harmful chemicals as do steel, copper or ABS. The caves are easy to make and decorate, and they provide the fish with another object for interaction. Most of the supplies needed are found at a department or hardware store.

Things You'll Need

  • PVC pipe
  • Measuring tape
  • Pencil
  • Hacksaw
  • 20-grit sandpaper
  • Substrate, sand or rocks
  • Cardboard or newspaper
  • Glue gun
  • Hot glue
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Instructions

    • 1

      Measure and cut the PVC pipe to the length you want for the cave to be. This will depend on the size of your aquarium and your tastes. Caves for small aquariums are normally 5 inches long. The diameter of your PVC pipe is relative to the size of the fish in the aquarium. A 4-inch PVC pipe is adequate for smaller fish.

    • 2

      Calculate three-quarters of the diameter of your PVC pipe. Measure the distance you calculated around the pipe and mark the pipe at the beginning and end of the three-quarters measurement. For example, if the PVC pipe has a 4-inch diameter, measure 3 inches around the pipe and place marks at the beginning and end of the measurement. This leaves a 3-inch section of pipe and a 1-inch section.

    • 3

      Cut the 1-inch section out of the pipe to create a "C" shape. The cut-out portion of the pipe is positioned on the bottom of the tank. With this section cut out, the pipe will sit flat on the floor of the aquarium and will not roll.

    • 4

      Sand down all the edges of the PVC pipe until they are smooth. The outside of the pipe can be roughed up to allow the glue to adhere better, but it is not required.

    • 5

      Set the pipe on a piece of cardboard or spread out newspaper.

    • 6

      Cover a small section of the outside of the pipe with glue and apply the substrate rocks or sand. This makes the pipe look more like a cave. If you have extra substrate from your aquarium, using it on the cave will make the cave blend into the bottom of the aquarium, and the cave will appear to be custom-made.

    • 7

      Rinse the cave under running cool water for 5 minutes and soak it in tap water for 24 hours.