You prolly already know, but adding more hiding places helps alot. I plan to have like one corner covered in fake/real plants, so shrimp and fish can hide. Mine does the same thing with plants, well the real ones actually, so thats why I plan to mix them in with fake plants, like have 1 real plant per 2 fake plants.
Good luck on finding driftwood/hollow log, I've been looking aswell, I came across some, but they wanted $40+ for small ones. If I coem across some more, I'll let you know.
Edit: Because I have very few hiding spots in the tank, my turtle does catch them, but I have seen a few live longer than I figured, they usually last a month or two.
But I found a decent look hollow log on ebay for around $20.,
here, maybe you like it, maybe you dont, I was really looking for something more realistic.