Suggestions for Herbivorve "Amazon" Plants

I'm setting my son's three silver dollars up in a 75g tank and I'd like some suggestions on low to medium-light plants I can put in that they won't eat.

I know they don't like ozelot or radican sword, but they'll eat anything delicate looking and light green.

I'd like something they won't eat that I can either float or that will grow to the surface and shade the tank in places. Silver Dollars like dim light.

Much thanks!

Roan

As a rule, they don't eat thick-leaved, dark green plants. They've never touched any of my ozelot or radican swords. They like thin-leaved, light green plants, like amazon swords.

Roan