Well, I did finally give in to curiosity and toss her into his bowl. And then I fidgeted nervously as I waited for them to tear each other apart.
First, she explored the new surroundings, as he kinda floated around in apparent confusion. "Something's not right... what's going on?"
Then she swam up to him and flared right at him, and he kind of "jumped" a little, but she swam off right away, so he swam after her and flared at her (he has such full fins, it's a pity they're not brighter) and then hurried up to the water surface and started blowing himself a nest!
Every so often, she'd drift over and check it out, but he'd shoo her away and keep blowing and rearranging bubbles. It was a pretty good nest, albeit a small one... Short notice, I suppose.
Then they did their chase around, and they each got a nip in the fin. Then he went back to his nest and I decided that if I'm going to breed them as a pair, they will need an adequate tank.
I haven't decided yet what to do about it...