Thanks - you're both reinforcing what I suspected, that things are fragile and it's better to wait for a bit. I used store ammonia to cycle it. I've been testing using the
API freshwater kit. The aquarium has been processing the ammonia for quite a while, now, but the nitrites took longer. I've done two large water changes trying to get the nitrates down, but they are still too high.
The poor julii just looks so stressed, chasing his reflection in the side of the tank. He does settle down and eat, though. Also, his fins aren't clamped down and he isn't gulping air. The betta seems in heaven, cruising around, investigating everything and flaring at his reflection.