I have successfully acclimated and started breeding these snails and plant from one of my other tanks. They seem to be very healthy.
Here is the plant... Not sure what species it is.
Snail.
If that plant is "Suesswassertang" (erroneously spelled "subwassertang" by non-German speakers), then it will rot away slowly. All freshwater plants will, even if they are touted as "brackish tolerant" by various people.