White clouds are incredibly adaptable fish so will survive even in the 78 deg F - 80 deg F dwarf gouramies prefer. However, this does decrease their lifespan and can make them a little more susceptible to diseases.
My real concern would be the volume of water we're talking about and whether or not you have proper filtration considering you're calling it only 'semi'-aquatic.
Provided the tank's large enough for all the minnows (how many do you have) and one dwarf and is quite well planted and filtered, it would be fine.