tarev, I've never had luck with Spathiphyllum (Peace Lily) growing in real wet soil but maybe it's because of our high humidity, with so much moisture in the air all time. Our daytime temps have been in the mid to upper 90's with lows in the mid 70's for over a month now, along with the high humidity. Years ago when I used strictly potting soil with no additives and watered once a week, I couldn't keep plants alive.
I found this neat photo with a Peace Lily growing in water and a Beta fish swimming in the vase:
http://www.bing.com/images/sea... and I have heard of some people growing Spathiphyllum strictly in water like the
Lucky Bamboo (Dracaena sanderiana) is sometimes sold and grown.
http://www.bing.com/images/sea...
I think I'll experiment and go take one of my Peace Lilies apart, wash off all the soil and put it in a vase of water to see how it does.