I got mine at quarter size ,and started him of in a 10 gallon. I do not think he would get nervous or lost in a 100 gallon much less a 10. Your frog is still going to trample those ferns unless you pot them ,you can bury the pot so only a little bit of the pot is showing. You actuly won't even be able to tell they are potted.

Your incredibly nice by the way! Giving him all those plants ,and even worrying about him getting nervous ! I bet you also sing to your flowers ,and have multiple bird feeders in your yard. How wonderful!!!