Here’s a link with the information from MN DNR website, you only need a license if you plan on leaving it on the ice overnight, no matter what type of fish house:
http://www.dnr.state.mn.us/licenses/fishing/index.html?type=fishing
Angling – dark house shelter (r) – Code 119
Description:
Dark houses, fish houses, and portable shelters placed on the ice for shelter while fishing do not need a license unless the house will be left unattended overnight. See fishing regulations book for display requirements Fishing House or Dark House.
Fishing regulations
Angling information
Fee:
$ 15.00