Well, Amazon sword is in the Echinodorus family, and it's listed here as a safe aquatic plant
http://www.redearslider.com/plants.htmlBut, I really struggle with this. I ended up building a freshwater refugium out of the old tank I bought off Craigslist just for the stand. I've got some Amazon sword, which is growing rather poorly, some Argentinian sword, and some Hygrophila corymbosa that grows like a weed. I've been trimming it back and tossing it out.
I know it pulls nitrates out of the water, which is a good thing. I'd love to feed some to my son's turtle, but I can't find any information on safety.
Are there stories out there of turtles poisoned by eating aquatic plants?
I know there are foods like broccoli and spinach that you should not feed, not so much because they are poisonous but because of long term damage due to the chemicals involved.
I just wish there were better resources for info on aquatic plants and turtles.