I have Golden Pothos (Epipremnum)thriving in several aquariums, roots in the water, stems and leaves out of the water. They grow like crazy, in moderate or better light.
I have heartleaf philodendron (P. cordatum) growing in lava rock as a sort of above the tank sump (water is pumped up from the tank, and is returned to the tank via gravity) It is growing well, though more controlled than the Pothos.
The fish and snails do not bother these plants. There are rarely any leaves under the water.
Some of the Pothos leaves are almost 1' long, giant heart shaped things! I have seen them growing outside where they limb trees and the leaves split like split leaf philodendron (Monstera sp,)
For more info on toxicity see the Wikipedia entry for Philodendron: http://en.wikipedia.org/wiki/Philodendron