Here is a great spearfishing tip.  It will screw into any standard pole.  Use it at sea or in lakes and ponds.

This item sports 5 prong steel sharp tips. Set screw is provided to keep tool attached to pole. Use an extension pole to reach longer distances. Order 2 of these tips and your price will be 25.00 as I will refund you $5.00 What are you waiting for?

Features

        - Simple and effective design

        - Screws into any standard pole

        - Safety guard included

        - Lightweight and easy to use