Overfeeding, and not chaning the water enough. That fog is a combination of phosphates and ammonia, which comes from decomposing wasted food and fish waste. You should change about 20% of the water once a week, and make sure to remove any uneaten food from the tank. When you change the water, you should age it for 24 hours to evaporate chloramines, you should also use a water conditioner.
If it is fogging up quickly, such as every couple of days, change the gravel or use a gravel vac, there may be waste trapped in the rocks.
alcohol is basicall condensation it causes fog just like hot and or cold water
bad heater core.
water goggles fog up by condensation when the heat is in your goggles its trapped and the plastic probably absorbs the cold in the water
evaporation
Brain fog is when your mind feels like a veil of fog has been placed around you, its hard to concentrate or think. There are 5 causes for brain fog. The causes include stress, chronic fatigue syndrome and fibromyalgia, nutrient deficiencies, depression, and fatigue.
The sun burns off fog through a process called evaporation. As the sun's rays warm the air, the water droplets in the fog begin to evaporate and turn into water vapor. This causes the fog to dissipate and clear up as the water vapor rises into the atmosphere.
boredom
Turn the conditioner when you are using the heater. It will decrease the humidity level (which causes windows to fog up.)
i won't say it
Clean it :) use a magnet cleaner or get some bright and clear chemicals to put in the water
Your breath.
fog or smog