Do some plants grow in water?

I have an 10 gal. fish/water garden that sits on my deck every summer (and is overwintered in a heated garage). Every summer, I buy a 4 pack of starter Impatiens and take them out of the flats, rinse off all dirt from the roots and put them in the fish tank. They absolutely love it, thrive, get huge and bloom profusely. In fact, they get so large that I have to take out half of them mid summer and plant in the garden....they take over the water garden and we can't see the fish. They don't keep over the winter in the 35 degree garage, so I take them out in the fall before moving the tank into the garage and throw them into the compost pile. Another great plant for a water garden is a green ivy house plant, which also thrives in water. I have a small pump in the tank so the water is always fresh. I don't know if the plants would do as well in stagnant water, but these two plants are a good variety for a large OR small water garden and much less expensive than buying pond plants.