Welcome to TPT!
Thanks! I've been lurking for quite a while learning more than I ever wanted to know about this hobby. About time I joined in the fun!
She (?) does indeed look like a dwarf neon rainbow fish. I'm starting to think she isn't happy with me since she's been kept mostly alone all this time and they are apparently a shoaling fish. Uh-oh! Right now she is in there with a small school on neon tetras and a couple ottos. Maybe I should get her a couple friends.
Thanks again for the ID. Now I finally know what to tell people who ask what type of fish she is!