going with my newer pair of serpae tetras, QT'd in the tenner. They still have healthy, vivid color and the fins are almost entirely grown back.
I've added a darker backdrop again- I think it is making the fish calmer. Spit doesn't look quite so pale when the light is on. They are starting to act aggressive over food- Spit tries to drive Ziggy away. Another week or two in here and then if all looks good I'll move them into the main tank.