A leaking aquarium creates a mess in the display area. Reseal the joint with silicon sealant to repair the leak. The sealant then needs to cure for 24 hours before you refill the tank.Continue Reading
Only use clear sealant on aquariums. Avoid sealants with mold or mildew inhibitors, which are also poisonous to fish. Read the manufacturer's label to ensure the sealant you choose is aquarium-safe.
Use a siphon to drain the aquarium 2 inches below the leak. If the leak is in a bottom seam, relocate the fish to a safe home for the time required to make the repair.
Use a single-edged razor blade to cut the old sealant away from the glass at least 2 inches on either side of the leak. The new sealant does not stick to the existing sealant, so clean the glass thoroughly.
Apply a bead of sealant in the area of the repair. Use the tip of your finger to press the sealant into the seam. Do not touch the repair again.
Keep the aquarium drained until the sealant has an opportunity to cure.
Replace the water in the aquarium. Once it is filled, look for any signs of leaks before returning the fish to the tank.