I've been growing (farming? lol) fruit flies for a few months now. I got the flightless kind, as if you catch and breed them you will get the ones that fly, which are quite a pain.
I would suggest getting some media with your first shupment but after that it is quite easy to make using mostly mashed potato flakes, sugar, yeast and vinegar.
They are GREAT for smaller CPs and seedlings. Plus, if you ever want to "play" with your plant it is nice to always have live food available.
You can grow them in any room with a decent temperature.
The only thing you have to worry about is letting some flying fruit flies breed with your flightless FFs, or when you open the container you will have tons of them swarming out into the air, and not into your plants.
It's actually a lot of fun. Just remember to only open your containers outdoors because you will almost always get a few escapees.
They are acrually kind of funny. For one, when you put some in your plant area, they dont wander around much looking for food. They sometimes just stand in the same place for days.
Also, they seem to "think" that they an fly.
Often, when they are on one of my pots which are in standing water...a movement will startle them and they will "jum", only to land in the water and drown.
Many of my feeding often wind up with the water that the plants stand in, looking like miniature Pearl Harbors, with FFs jumping to their deaths.