Does STT ever have a market for fish or produce? I'm mostly curious if there is a place to get fresh fish that you didn't fish for yourself...
Yes, but they're very small with limited selections. You can get fresh fish at Market Square in town, Frenchtown (very early in the morning), around the stadium, in Smith Bay near the entrance to Coral World, and on the weekends on the Waterfront from a boat that docks across from The Greenhouse.
For fresh produce, Market Square on Sat (get there early a.m.), Bordeaux Farmers Market last Sunday of every month, Yacht Haven Grande on 1st and 3rd Sundays, corner of Donoe and Skyline on Fridays, and maybe somewhere else I don't know about. Most of the roadside stands sell produce imported from Dominica, whereas the aforementioned is usually grown here or on St Croix.
Most people shop at The Fruit Bowl on Sun or Mon for a wider, imported selection.