Have you thought about zebra danios? They were the first fish I bred, and the info below could also be applied to some other danio species.
First thing is to sex the fish - if they’re in prime breeding condition, this should be quite clear- but can depend on variety! So I’ve included a few things to look for below:
The females will be larger than the male, with a rounded belly indicating she’s carrying eggs.Body colouration silver with blue stripes, and pale yellow fins.
The males will be smaller with a more streamlined body. They will be darker in colour (possibly viewed more gold/purple) with blue stripes, with golden fins.
If you look at the female from the side, you might be able to see the egg depositor in front of the anal fin (this is only present on the female). If you look at the male from above you might be able to see breeding tubercles on its pectoral fins (these are only present on the male).
I would use a separate tank for breeding with mesh or gravel over the base for the eggs to fall through where the parents can’t get them.
Add fish in good breeding condition to the tank in the evening - you can put one male and one female, if you put more fish I would add more females than males as the males may decide to focus on sparring off with each other instead of breeding!
Danios will typically lay their eggs at first light in the morning - you’ll see the male chasing and pressing against the female.
Once this is done (or light has been up for a few hours), remove the adult fish from the tank.
Hope this helps!
London