We set up a little habitat with them in a plastic container with pond water and rocks (so they can climb out of the water when they become air breathers) and just left it outside. I figured they lived outside in the pond, so being outside would be best. A couple of weeks ago, we went and got a 5 gallon bucket of pond water and have been cleaning their container every week. I also started feeding them spinach every day or every other day (boiled down, then chopped and frozen).
We finally noticed some hind legs last week and saw the first one with front legs today! It should be just a couple of more weeks before it completes metamorphosis and is a full fledged frog.
*You can click to enlarge the photo.
It's been a fun little science experiment. I'm actually surprised they are ALL still alive. ;)