After another week, the filter seems to have the ammonia situation under control and it seemed like a good time to add some fish.
I had a small group of chili rasboras in my home tank that were kind of lost in a larger group of M. kubotai (and unhappy in the higher flow that the kubotai prefer) so I've decided to bring them to work.
They're still a bit pale from the move, but they should colour back up in time and I think they're the perfect size for this tank.
I also have some fire red shrimp that will go in here eventually, but I'm scared about what they might do to the HC before it gets fully rooted.