Sometimes you just need a filtering blade that's a little smaller than the normal 6 inch blade, for smaller fish and for removing ribs I like a 4.5 inch blade, so not being able to buy one like that I thought I'd modify a knife to make one.
I bought a couple of rockingham forge utility knives these are great for the price, but I decided to modify one so that it is slimmer and more flexible.
I ground the spine down and curved the tip up to enable me to work round the bones more easily.
The bonus was it also made the knife much more flexible.
Now to catch the fish !!