Remember to have a good knife with you when spear fishing, whether you're free diving or using scuba equipment. It's just as important as having a spear gun. You need a dive knife for two main reasons:
- You should have a knife accessible to quickly and humanely kill fish you have speared.
- You should have a knife available to help cut yourself out of a jam if you get tangled in someone else's line or rope.
You don't need to spend a lot on a knife but get a small, sharp serrated blade and have it easily available to you.