not sure how new you are to fish keeping. I was having the same problem a while back. You might be having the dreaded mini-cycle aka "new tank syndrome" going on.
The cloudiness looks like really super fine bubble or dust floating in your tank? White in color? Sort of looks like someone in your tank has been sanding joint compound.
Keep on doing partial water changes (daily), check your water with a test kit daily, don't add any more fish.
I thought it was all sorts of "contaminates" or such.
How old is your set up? Did you let it cycle properly? Did you change the filter media recently (or run it under tap water)? Did you add more then 3 fish a little bit before it happened?
Like I said it happened to me a few months ago, and sounds very similar to a mini-cycle.