There is a saying in the ancient book: "Draw water into the zero hall". "Zero Hall" is the decline that leads to bad luck. The original intention of "dividing water into zero hall" is to introduce water into the position of bad luck, which can turn disasters into blessings and turn disasters into safety.
The most taboo place in the fish tank is behind the sofa. Li Xiangdong also said in "Common Sense of Feng Shui" that it is not advisable to rely on water, which is impermanent and unstable. Therefore, if the fish tank is placed behind the sofa and the family sits here every day, there will be no "mountain" and the family will be unstable. Of course, you can choose to put the fish tank around the sofa, so there is no obstacle.