How to Make a Crab Cave in an Aquarium

If you plan to keep crabs and other crustaceans in your fish tank, you must build a safe and secure environment for them. Crabs can be very shy and sensitive, and one of the best ways to keep them safe and healthy is with a series of caves. Building a network of rock caves within the tank gives the crabs a safe place to hide from their more aggressive tank mates. These caves also help recreate the natural environment crabs enjoy in the wild.

Things You'll Need

  • Flat rocks
  • Bucket
  • Aquarium-safe sealant
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Instructions

    • 1

      Find or purchase an assortment of flat rocks you can put together to create caves. When keeping crabs in an aquarium, it is important to size the cave to the crab. Crabs like a small, safe and secure place to hide, so placing several small caves throughout the tank is generally better than designing a single large cave.

    • 2

      Clean the rocks thoroughly with hot water. Do not use bleach or other chemicals. These chemicals could leach into the water and harm the crabs and fish. Set the rocks out to dry, preferably in a sunny location. The rocks should be completely dry before you move on to the next step.

    • 3

      Glue the rocks together to form caves. Use an aquarium-safe sealant to glue the rocks together. Create a cave that is closed on three sides, with an opening at the front for the crabs to enter and exit.

    • 4

      Place the crab caves in the corners of the aquarium, and arrange them so they look good in the tank. If you have a large tank, you may want to include several more crab caves in the center, with some in the back and some closer to the front.