Adamant harpoon

The adamant harpoon is a tool used for harpooning fish in the Fishing skill and is capable of catching 80% more fish than a regular harpoon. It requires an Attack level of 40 wield, but a Fishing level of 31 to use. The harpoon can be smithed using the Smithing skill at level 73 Smithing, using one adamant bar on an anvil. The harpoon may also be gained as a drop from Celestial water warriors as an uncommon drop, but there's very high leveled requirements to fight these creatures.