Hydrocotyle verticillata

Unlike other Hydrocotyle species, this plant maintains its upright growth habit. Verticillata originates from the Americas and reaches 3-7 cm in height. Ideal growth is achieved only in bright light and soft, slightly acidic water. It does not need to be rooted as it can be used as a floating plant.
Hydrocotyle verticillata is definitely a top-tier plant.

If the soil is kept moist, you can even use it as a houseplant.