The Frost Fire 6” filet knife features a narrow, curved, flexible blade, perfect for descaling, deboning, fileting, skinning, trimming, and butterflying fish and poultry. Razor-sharp and ready to filet. The Frost Fire 6” filet knife features a narrow, curved, flexible blade, perfect for descaling, deboning, fileting, skinning, trimming, and butterflying fish and poultry. Razor-sharp and ready to filet. The Frost Fire Series – a collection of light-weight, razor-sharp, knives with an icy cold look, and fiery effective performance.