Aqueon Silicone Sealant High strength silicone creates a waterproof, permanent seal that will not crack or shrink Permanently flexible silicone Long-lasting bond stops leaks Easy to apply 100% Non-toxic silicone Our 100-percent silicone aquarium sealant is easy to apply and waterproof to stop leaks The high strength silicone creates a permanent seal that will not crack Or shrink and is non-toxic making it perfect for use on all aquariums For standard aquariums use clear and Black Seal aquariums use Black sealant Our 100% silicone aquarium sealant is easy to apply and waterproof to stop leaks The high strength silicone creates a permanent seal that will not crack Or shrink and is non-toxic making it perfect for use on all aquariums