(3 Pack) Aqueon Silicone Sealant 3 Ounce each Pack of Three 3oz Silicone Tubes 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. For standard aquariums use clear and Black Seal aquariums use Black sealant.