Aquarium Putty & Sealants
Keep aquarium sealants around in case a quick repair is needed - a crack in your tank, for example. Use aquarium putty to situate coral fragments on coral mounts or live rock. Or, apply to the base of heavy rocks for no-slip protection against cracks and scrapes. Aquarium putty and sealants have as many uses as you can think of!
Never use a glue, putty or sealant that isn't specified for aquarium use, as they can be toxic.