The Fish Scaler tool is a multi-purpose fishing tool only available on some 91mm knife models. The ridged bottom edge of the tool is the fish scale remover. The tip is a "U"-shaped fish hook disgorger used to safely remove a hook from a fish's mouth. The tip is magnetized on some versions, empirical evidence suggests those models manufactured prior to 1985.

On the back side of most of these tools is a Ruler with gradations most commonly in inches. Newer versions have a metric scale on one side and an imperial scale on the other. Very early versions of the tool do not have any ruler markings.

A novel usage for the Fish Scaler appears to be Halloween Pumpkin Carving; the wide serrations are apparently ideal and because the tool is safe for younger carvers it might even be the best suited tool for the job ever.