It appears this knife was a promotional item for a fish pesticide, I did some searching on both names. The company went bankrupt and the PRONOX Fish is the actual pesticide. I thought I was going to find an old tackle company when searching the name.
Interestingly, my father had almost the same knife (he is 80) and recently gave it to one of his grandsons. I used to carry the knife as a kid but left it with Dad after I grew up. I assume my father picked it up in a local tackle shop a long time ago. Dad's version looks to be of more recent vintage but pretty much the same model. I used to have people offer me money for the knife when I carried it as a kid.
Jack