What Kind of Silicone Can I Use on an Aquarium?

Silicone rubber sealant is an essential tool for home aquarists. This versatile gel repairs leaks, seals seams and bonds objects without upsetting the chemical balance of the environment. Most aquarium-specific silicone is safe for freshwater and saltwater environments.

  1. Material

    • Pure silicone rubber is safe for aquarium use. It is usually transparent straight out of the tube or turns clear upon drying to minimize its appearance.

    Uses

    • Aquarium-safe silicone rubber seals cracks in glass and acrylic fish tanks and repairs leaks along seams. Experienced home aquarists also use sealant to construct homemade aquariums out of plate glass. Sealant is a useful tool for creating aquascapes: it can join rocks to form a cave or bond lightweight driftwood to a heavier object to prevent floating.

    Flexibility

    • Once set and cured, aquarium-safe silicone will remain flexible to accommodate the water pressure in the aquarium. Its rubbery texture resists cracking from changes in temperature or immersion.

    Safety

    • Silicone sealants sold in pet stores or aquarium supply shops usually have safety labels. These sealants will not leech chemicals or degrade in the water and are generally safe for freshwater and saltwater tanks. Sealants sold in hardware stores might not specify their safety for fish tanks and could contain toxins.

    Types

    • In addition to silicone rubber gel, aquarium sealant is also sold in sticks of moldable epoxy putty and glues formulated for marine use.