Pond snail q's - pic of leaf

[Naomi Mizumoto <naomizu at mac_com>]

Back with the same question and a link to a photo.

http://photos.yahoo.com/bc/mizmo_naomi/lst?.dir=/My+Photos&.src=ph&.order=&.view=t&.done=http%3a//photos.yahoo.com/

It was taken before the problem got out of hand, but you can see the leaf 
on the stem in the upper-left-hand area - it has the two holes. Now there 
are many more holes and the transparent specks on almost every leaf on 
every stem. Does it look like the evil-doings of a pond snail or can a 
deficiency alone cause this?

I'm so sorry if I'm being pesky-persistent, but this is my new "favorite 
plant" and I'm worried after what happened with my old "favorite plant." 
Thanks for any help/advice you can send my way...

-Naomi