[Tagging] Decorative pool?

[Nathan Edgars II]

What's the correct tag for a small decorative pool like this?
http://maps.google.com/maps?ll=28.540045,-81.378424&spn=0.000987,0.002575&t=k&z=20&layer=c&cbll=28.540331,-81.378715&panoid=i0K7FBmQ_sgIfvQ9U6mOJA&cbp=12,146.51,,0,2.8
I used natural=water but that seems totally wrong. (I know about
amenity=fountain, but (a) that would be a node inside the pool and (b)
these don't always have fountains.)