SAEs eating plants (Mayaca & Rotala)

These dogone fish seem to have developed a real appetite for my
Mayaca. I suspect they are also the culprits who're responsible
for eating my Rotala species and another plant I'm not sure of.

This is the plant I got from Erik Olson about a year ago. It looks 
most like Eichhornia natans on pg 15 Vol 3 of the Baench atlas or 
Eichhornia diversifolia, pg 49 Baench Vol 2. The stem and leaves are 
quite fragile and the leaves blacken if damaged. The leaf is entire 
and clasping (leaf attaches directly to the stem) very close together 
at the growing tip, light green, about 5mm wide and 2-3 cm in length.
Erik, did you ever make a positive identification?

Anybody else have problems with SAEs eating plants? Anybody in
Vancouver area want some well fed adult SAEs? $10 ea.