I think that's Indian Fern -Ceratopteris Thalictroides
Not sure if it's known by any another name...
I have a ton of it in my tank. It's a cool plant, but keep up with it. Grows fast, it breaks off sprouts that float, grow and shadow the tank.
The leaves of the Water Wisteria depend on the temperature of the water - at higher temperatures they are large with more space between them; however if the temperature is lower they are smaller and much closer together!