Good feng shui? Will a single betta fish in a small bowl attract good feng shui?

I have several betta fish in individual bowls or vases (large and small) in different rooms of my house. Is this good or bad for feng shui purposes? I keep the water very clean, but I wonder if this type of lone dwelling fish attracts positive energy or negative?

there is no fish out there that will attract good fengshui! it is not the fish! the secret lies in the location/ direction where you put the water (where the fish is). in fengshui, the flying stars concept/ technique is used to calculate for the location of the good chi and the bad chi in your house. it also describes their individual characteristics. when you use a specific area, you "activate" that area, making the characteristic of the chi to happen in our reality. for example, an area has a bad chi, when you use the area, then the bad thing will happen. there are many ways to activate an area. one of which is to put a moving water, or water with an aerator as in an aquarium. fengshui people like to mislead their audiences so that you won't know their trade secrets, hence they emphasize the kinds/ colors/ number of fishes to use.
regarding flying stars, the emphasis is the location of the chi, and remember that not all chi is good, there are also bad chi. in flying stars, 3 sets of 1-9 are "flown" in a tic-tac-toe grid (3 rows by 3 columns); 3 sets representing mountain (health), water (money), and base/time. the calculation is based on the facing degree of your front door or most yang door of your house, and move-in date or when did you first used your house. you will end up with 9 sets of 3 number combinations. each number is represented by an element, characteristic, material, family member, etc.; when the numbers combine they interact and form new energy, this is the energy of the location in the house. so, using this technique, you can analyze where to put your kitchen, bedroom, living room, bathrooms, etc. and activate the good areas by using them or putting aquariums or moving water features; and leave the avoid using where the bad energy is.

According to Eight Mansions Feng Shui, the north sector is about "career" and is related to the number "1", the element "water", the color "black". So it is believed that for symbolism purposes if you place one black fish in a bowl of water, it will help your career.
However, there are other sectors where you can place this symbolism because water feeds wood in Feng Shui so one element enhances the other. These areas are the East for Health and the Southeast for Wealth.
I love this aspect of Feng Shui and find that visualization, in general, is a wonderful thing however, it does take a lot of self-work in conjunction -- after all, nothing happens by magic. You have to want these changes deep-down -- you have to believe they are possible -- or else you might be just wasting your time.

On a more technical level, the south east corner is the one most people have heard about. In feng shui, it is the wealth corner, once again fill it with greens. A small water feature in this sector is excellent as are any symbols of water, including fishes and frogs.
If you calculate your Kua you can find out more, for example for Kua 2 - The Northeast sector is your prosperity location. You would also do well to place a Goldfish bowl, Aquarium, miniature fountain, or pictures of water scenes in this location. You might also use floating candles in this area.