There is a fish hatchery in North Attleboro, right on the Mansfield line. It has been a while since I've been there but it used to be open until 4pm on Saturdays.
I would like to see the hatchery myself and I think my kids would love it. They really like Bass Pro shops. The fish are great to see and the laser rifle shooting range is always a big hit.
May the holes in your net be no larger than the fish in it - Irish Blessing