I don't see why not. I fished often from our pram dinghy when I lived aboard the sailboat. I knew, and still know, many who do that.

In fact, here's a pic of my wife fishing in Espritu Santos Bay from our 6'6" dink. Not with a fly rod unfortunately- she doesn't use them. That particular pram is a B and B yacht designs Minipaw. There are literally tons of designs out there that can be quickly built, fairly inexpensively.