How to Fix Cracked Glass in a Fish Tank

Even the smallest crack in a glass fish tank can lead to expensive damages. If untended, a small crack can grow larger and the pressure of the water in your tank may cause an entire wall of the tank to blow out. If this happens, your fish may die, you will likely have to buy a new tank and you may be facing expensive restoration or replacement costs for furniture or flooring. Do not overlook even the smallest crack --- a simple repair can save you the cost of buying a new tank.

Things You'll Need

  • Backup tank
  • Paper towels
  • Silicone aquarium sealant
  • Scrap pieces of glass
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Instructions

    • 1

      Relocate the fish in your cracked aquarium to another tank or house them in smaller, temporary containers. Take all plants, decorations and substrate out of the tank and drain the water out slowly to avoid putting pressure on the crack in the glass.

    • 2

      Soak up excess water in the tank with an old towel and use paper towels to completely dry the glass.

    • 3

      Apply a layer of silicone sealant to the crack itself, as well as to the surrounding area, on the inside of the tank.

    • 4

      Affix a scrap piece of glass to the inside of the tank at the site of the crack and, using phone books or clamps, apply pressure to the new piece of glass until the sealant dries. It is best to use a piece of glass of approximately the same thickness and, preferably, the same type of glass used in the cracked fish tank.

    • 5

      Fill the fish tank with water and allow it to sit for 24 hours. If there are no leaks, drain the tank and refill it with water appropriately conditioned for the type of fish you have.