Fish often look "happy" right up to the point of death from toxic water. Sorry, not to be mean, but I think you made a big mistake adding this huge load of fish to an uncycled tank. Here's my advice for possibly saving them:
1. See if you can get some Bio-Spira to add to the tank which will get it cycled quicker (don't let the LFS talk you into "Cycle" or another product.)
AND/OR
2. See if your LFS or a friend will give you some used filter media or at least a couple handfulls of gravel from an established tank to add to your tank (just plain dirty tank water won't help much - it has to be something that the bacteria are living on) This will also speed up your cycle.
3. You must have a test kit - test ammonia every day and change enough water to keep the ammonia under 2.0 (under 1.0 = even better) which will probably mean every day or even twice a day.
If you can't keep the ammonia under control, be prepared to loose fish, you very well might start to see things like ich and velvet start to appear as the stress weakens them. Another idea is to get another tank right now and divide the fish up between them, as you will have to do that in the near future anyway, as they outgrow the 10 g. and cycle them both at the same time with a smaller bio-load in each tank.
