Happy day....I'm one of those people that says "Do nothing....the fish knows what to do." If you wanted to really do something, consider searching on the words "how to breed zebra danio" and see what you come back with. There might even be a youtube video about the topic. That would be the best way to learn what to do.
You know...it could also be a plus-sized danio. I'm not totally sure how it works among fish, but plus-sized humans are deeply offended if you presume they are pregnant. Or if they are pregnant, and you just presume they were plus-sized, that's just as bad. I think there's less to fear from angering a plus-sized danio vs. a plus-sized human (danios seem to lack the opposable thumb needed to grip items to throw), so all and all, just choose how much you care and set your learning to that level.