How to Repair Cracked Glass in an Aquarium

Written by kimberly sharpe Google
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How to Repair Cracked Glass in an Aquarium
If aquarium glass cracks, the entire panel should be replaced. (aquarium fish 8 image by cherie from

A glass aquarium is constructed with four or five panels held together by framing and a silicon sealant. When a glass pane sustains a crack it is best to fix the entire pane to prevent future damage from occurring. Completely replacing the glass pane will increase the chances that the small crack leads to a major break that could destroy the aquarium.

Skill level:

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Things you need

  • Replacement aquarium or large bowl
  • Fish net
  • 100 per cent pure silicone sealant
  • Razor blade
  • Glass

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  1. 1

    Catch the fish using a fish net. Place the fish into another aquarium or bowl until the broken aquarium glass pane is fixed.

  2. 2

    Work a razor blade carefully under the frame of the cracked glass. Chip away slowly at the silicone sealant and pry away the frame that holds the glass pane in place. The silicone sealant will need to be removed from the inside of the fish tank along the damaged pane and also along the plastic frame on the outside.

  3. 3

    Pry the plastic frame pieces away from the cracked glass and set them aside. Gently pry away the broken pane of glass from the silicone sealant.

  4. 4

    Measure the area where the broken piece of aquarium glass was. Take the damaged piece of glass with you to a glass store so it can be easily matched. That store should be able to cut and wrap a new piece of aquarium glass for you.

  5. 5

    Apply a thin line of silicone sealant to the edges of the new pane of glass. Fit the new pane of glass into the existing space where the old pane was.

  6. 6

    Apply silicone sealant to the plastic frame pieces. Place the plastic frame pieces into place along the edges of the new glass. Press lightly so the sealant hold firmly.

  7. 7

    Place a thin bead of silicone sealant inside the corners of the aquarium where the new pane of glass meets the old glass and the aquarium's bottom.

  8. 8

    Leave the aquarium alone for at least 24 hours while the sealant cures. After 24 hours, use a razor blade to gently scrape away any dried silicone sealant that has leaked out to discolour the glass.

  9. 9

    Fill the aquarium with water and allow it to sit for one or two days before placing any fish in it. The corners of the glass must not leak where it is sealed to the old glass. If any leaks occur, remove the water, dry the surface and reapply more silicone sealant. Allow the sealant to thoroughly dry. Refill the tank with water and recheck for leaks.

Tips and warnings

  • Silicone can produce a strong odour. Repair the aquarium in a well ventilated location.

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