Have your tank already cycled? If not, then it is very important for you to understand and perform the cycle. It involves colonizing a bacterial culture in your tank that will eliminate dangerous ammonia and nitrite in your tank. In the Fishlore homepage, you will see the "Aquarium Nitrogen Cycle" under the Tropical Fish Beginners Guide. In that article you will understand the process. (I don't know how to post the link......hehe sorry)
About the cloudy tank............it's either caused from adding a lot of fish at a time or dust from your substrate(gravel or sand). If you add a lot of fish at once(the general guideline is to add one or two fishes at a time, then wait for 5 days before you can add another pair again), then your tank is performing a mini-cycle because the filter was "traumatized" because too much bioload is added at the same time..........If it didn't happen because of adding a lot of fish, then it is caused by the dust the gravel expelled when you added the water. Even if you rinse the gravel VERY thoroughly, there will still be dust in the water. It won't bother your fish and will settle down in a few days.
Good luck!
