I'm pretty sure Aral Sea is saltwater.
Anyways, the top lakes by volume are
1. Baikal, in Siberia - 23,600 cubic km (5,700 cubic miles)
2. Tanganyika, in Africa - 18,900 cubic km (4,500 cu mi)
3. Superior (Canada/US) - 11,600 cubic km (2,800 cu mi)
Interesting to note that Baikal in...