Hello and welcome to FF! A 20L ($20 at PETCO until Sep 27) is a better tank to house your frog. Not using soil will prevent you from doing anything close to their natural environment. If you want to go all artificial can use basking platforms made for turtles (i.e. Zoo Meds Turtle Dock) and soft weighted artificial plants in the water area with no substrate and a canister filter rated at least 10X the actual water volume. Good luck !