Awesome! I love it! It is beautiful.
The other wonderful thing about it is that my husband would love it. He would pick something to live on the land (reptiles, amphibians, insects, arachnids... he loves them all). And I would pick the plants and fish. And then we would both live happily ever after... until his turtle eats my fish. Huh.
Well, maybe I will live my little dream through YOUR paludarium. What do you think of that idea?
Newts or fire bellied frogs would be fine and go in and out of the water. Don't get a turtle, they'll wreck it and make a mess.
A spider seems like it would be fine as would most lizards I guess, though you would probably need more space. If you built enough space in, carolina anoles would probably be fine. I've seen them swim to shore when dropped in water.