Rescue your fish!

How to reseal an aquarium with aquarium safe sealant

Fish tank sprung a leak? No worries, your fish and home are still safe! Learn how to reseal an aquarium with our helpful guide. We’ll explain what you need and how to do it.

How to repair an aquarium leak: Leak tests and tools needed for a repair

A compromised aquarium seal is big trouble for your underwater friends. To do a leak test, simply grab paper towels and run them along the seams of the aquarium. If water is seeping through the seams, the paper towel will easily pick it up. If any moisture transfers to the paper towel, you need to repair your tank.

Here are the tools needed to reseal an aquarium…

  • Waterproof and fish safe silicone sealant
  • Straight razor – or another sharp tool for removing old sealant bead
  • Acetone
  • Old cloth
  • Containers – to hold your fish while you complete the job

How to reseal a fish tank: Step by step

We recommend completely draining the tank. New sealant doesn’t always bond well with the old. Avoid problems down the road by simply replacing the entire bead.

Here’s how to seal a leaking fish tank…

  1. Remove the fish and completely drain and clean the tank.
  2. Remove the old sealant with a straight razor.
  3. Clean the old residue off with acetone. Make sure the entire joint is free from old sealant, this will ensure a solid seal with the new bead.
  4. Apply a ¼” bead of aquarium sealant along the outside of the joint. Then move to the interior of the tank and repeat the process. Make sure all glass walls are separated by the silicone bead, and there are no air bubbles trapped in the seal. Intense water pressure can push the sealant loose, so don’t forget to apply the inner bead of sealant! The interior bead will help reinforce the strength of the sealant.
  5. Repeat the process on all other joints.
  6. Allow cure time to be reached before filling the tank with water.
  7. Refill the tank 3 inches at a time, to make sure your seam is secure.

How to seal an aquarium: Which sealant is the best for the job    

Choosing a fish safe silicone sealant is necessary to protect your tank and fish. When selecting an aquarium sealant, make sure it’s salt and freshwater compatible, holds up under constant submersion, and has a non-toxic formula. Always check the product information to make sure that the sealant is suitable for the size of your tank.

For an aquarium safe glue that checks all the boxes, reach for Loctite Clear Silicone Waterproof Sealant. This specialized formula is 100% fish safe and designed to provide the right kind of seal for any tank under 30 gallons.

If the glass itself is cracked, you need a new pane of glass. Aquarium sealants aren’t designed to hold broken glass together under intense water pressure.