silicone sealant
The 100% silicone aquarium sealant is easy to apply to stop leaks. High-strength silicone creates a permanent airtight seal that won't crack or shrink. It is formulated to be non-toxic, making it perfect for use in all aquariums.
Waterproof seal stops leaks Permanently flexible; won't crack or shrink Easy to apply long lasting bond 100% non-toxic silicone for use in fresh or saltwater aquariums Transparent silicone color - also available in black silicone