Keeping a goldfish in a bowl at the entrance or small bamboo shoots will bring prosperity. Lot of Feng Shui consultant will tell you this to improve the positive energy of your home. But no one will tell you why? Why you need to keep fishes and plants in your rooms and at the entrance.

But, yes if kept in the corners of your house is an indicator about the quality and purity of the water you are consuming and the air you are breathing.

Why?

Gold fish being very sensitive to toxins in the water will float upside down if the water quality is not good. So it tells you if you should drink or change the water as it is not good for consuming.

The tiny plants also tell you if your rooms are getting enough sunlight and fresh air for it to survive or not.

Keep such plant in all rooms and see which plant wilts assuming your fish is fine!    

There must be one of the reasons for its wilting while others are doing great! Sunlight not enough or oxygen not enough.

Such poor quality oxygen rooms must be avoided for small kids and sleeping. Or try to improve the air quality by additional window or ventilators or even an AC.

Sunlight is critically important for  healthy rooms, so try to open all windows and doors during the morning times for the good ultra violet rays to kill all germs in the rooms. 

So you know why keeping a gold fish or bamboo shoot will not improve your home energy, they are live indicators of the quality and purity of the essentials of the life.