Opinel slimline filleting knife boning out fresh mackerel 

This particular model of Opinel, the slimline, has a long thin stainless steel blade and a bubinga wood handle. I find it perfect for filleting fish. A great blade to take on a fishing holiday, but it is an evil looking thing so be sure to pack it in your hold luggage, not your pocket!
In Britain, the state has effectively criminalised the carrying of knives in public places. this is because some people stab each other. Of course, they ignore the law while honest citizens like me who often have a sharp penknife in their pockets now live in fear of both criminals AND police.