hmm at petsmart they sell Marina brand plants I just got an orange and pink one(they called it a red ludwiga) that is super soft.My advice would be to go to your LPS and see what you can find that you think is safe.I also got a gel corral looking thing that my fish loves it's very soft and he likes to sleep in it.
Here are some links:
The gel plant thing here is one of the two online I have an orange one I couldn't find on the site there are 4 or 5 different kinds.
These ones are small but I have two of the blue ones a orange one a pink one and a green and red one they have not caused any problems for me. http://www.petsmart.com/product/inde...n=Product+Type
I have this and it's nice it just sits at the bottom of the tank but my tail bitter seems to get alot of interest out of it when I put it in there.