Worked about five years in a fish cleaning service for a charter boat fleet. Our knives were Dexter Russel. We used a F.Dick hypersteel to touch up the blades. We mostly filleted tuna, Mahi, and wahoo.

the other option is to buy a knife like Havalon where they change the blades out i know most now make a fillet model and actually have thought about buying one myself

I have both Rapala and Buck. They both work well.

Opinel makes a great folding fillet knife in different sizes.