Top 10 Aquarium Sealants for DIY Repairs in 2027

Seachem Silicone Sealant is a 100% RTV silicone rubber that Seachem says is safe for freshwater and saltwater aquatic life. It comes in an 85 g (3 oz) tube in Black or Clear. Seachem notes an acetic acid (vinegar-like) odor while it cures and does not publish a price.

Aqueon calls its sealant 100% silicone and 100% non-toxic for freshwater or saltwater aquariums. It is sold in 3 oz and 10 oz sizes, in Clear or Black. Aqueon lists no price; Aquarium Depot sells the 3 oz clear for C$16.23.

Marineland describes its sealant as non-toxic for freshwater and saltwater aquariums, permanently flexible, and the same-strength silicone used to manufacture new aquariums. PetSmart lists it at $8.99 online.

Selleys Glass Silicone is a 100% silicone with an acetic acid cure that skins in about 5 to 10 minutes and typically cures in 72 hours. Selleys says it is suitable for constructing and repairing small aquariums and to allow 7 days to cure before refilling and adding fish.

The Betta Clear sealant is a 100% RTV silicone with no solvents or acetic acid, in a 310 ml cartridge, cured in 24–48 hours. Complete Aquatics lists it at £13.49 and labels it 100% aquarium-safe once fully cured, but the same page says it resists mould and mildew, so check the tube label.

Seachem CoralCrete is a two-part epoxy putty that begins curing in about 5 minutes, hardens in about 15 minutes and is fully cured after 24 hours, submerged or emerged. It comes in 57 g (2 oz) and 114 g (4 oz), in purple or gray.

AquaStik is a clay-like epoxy putty that hardens in about 20 minutes, fully cures in 24 hours and cures underwater. It bonds to wood, concrete, ceramic, acrylic, metal and fiberglass. Bulk Reef Supply lists it at $12.83 for 2 oz and $14.89 for 4 oz and advises against using it to fix a leak.

Nyos Reef Putty is a silicone-free two-component epoxy that can be used above water or underwater. Processing time is approx. 45 minutes, initial set after approx. 3 hours and full strength after approx. 24 hours. Charterhouse Aquatics lists 200 g at £12.95.

Charterhouse Putty is a two-part epoxy putty with ceramic filler and a 5-10 minute set time. It bonds ceramic, stone, wood, rock, plastic, glass and metal and is listed as safe for all aquariums, ponds, vivariums and terrariums, at £9.15.

Milliput Standard is a two-part epoxy putty that Fishkeeper lists for saltwater and freshwater aquariums and other underwater applications, including repairing pipework and equipment and bonding items to aquarium glass. It is stickier than most epoxies and costs £7.00, available in selected stores only.