White cloudy water is generally associated with a bacterial bloom. The bacteria won't harm the fish but the cause of the bacteria is generally poor water which will harm them.
Overfeeding is a definate cuase here. The fish will consume enough food in about 1 to 2 minutes, so any extra food will either be eaten and pooped out or just rot in the tank. If possible have your wife not feed the fish for a couple of days or else for the next week or so just every other day. They will not starve to death. And start to do daily water changes. It could take awhile but the bacteria will die off and you will have clear water again. At a minimum you should be aiming for a weekly 20-30% water change which a lot for your tank but is needed to keep the fish nice and healthy.
Do you have water test kits for ammonia, nitrite and pH etc... These are helpful in finding if there is a problem with your water.
Also is that a 150 liter or gallon tank? And what sort of filter do you have?
