How often are you supposed to clean a smoking bowl?

Bowls are the most difficult thing to keep fish in. The only fish that can easily be kept in a bowl is a Siamese Fighting Fish. Goldfish should be kept in an aquarium with filtration. The secret to keeping a bowl is to do regular water changes. NEVER change all the water in the bowl. My prefered method is scoop out about half of the water from the bowl into a clean container. Place the fish in the container. Then using a clean sponge wipe down the sides of the bowl and stir up the gravel. Tip the water out of the bowl (water your plants with it). Half fill the bowl with treated water (never put chlorinated tap water straight in). Then top it up with the water you saved from the bowl and put the fish back in. A fish bowl will go smoky because your balance of "good" and "bad" bacteria is out of balance. The smoke is actually "bad" bacteria in the water. It takes about six weeks for the "good" bacteria to develope properly. NEVER clean out all the water from your bowl or wash the gravel, this will kill the good bacteria. Also be very careful with how much food you give the fish. Use only a good quality food and feed very small amounts. It is surprising how little food your fish requires. Excess food and cheapo food will cause your water to go smokey much faster. Depending on the size of your bowl, you should clean it every week.