I left the female with the male overnight. They have been together almost 24 hours and haven't spawned yet. Every time the male tries to get her to do the mating dance, she just swims away and hides. Should I give them until the morning, or go ahead and spawn my back up female instead?
My first spawn took the pair about 72 hours together (Mostly unsupervised) to actually commit the dirty deed of spawning.
they just kinda flirted with each other the first 48 hours, and then he made his nest at the very last possible moment, and she finally understood "Hey theres a reason as to why this guy keeps running up to me and dancing then running back to this collection of bubbles at the top of the water" and alas they finially embraced.
But dont worry about missing out on the action, both of my spawns lasted about 2-4 hours each. (i mean the 2 betta embracing each other, and collecting eggs and putting them to the top, etc etc) so unless the decide to spawn at like midnight, you should absolutely fine.
And i wouldnt worry about minimal nipping, it will all heal, unless your boy or girl is taking out chunks, of fin (and i mean noticable, like a couple CM)
i mean if i was a guy betta and i sat there and danced and danced for a female and she never understood what i ment, i'd get a little upset myself, and considering male bettas are housed by themselves, its not like they have very cunning sociable skills to other fish.
EDIT: if you dont wanna read this wall of text this is for you: Leave them together until they spawn, because its not like they will instantly do it, only remove one of them if a serious chunk of fin has gotten taken out, (or any other serious injuries :P) and for the most part, just let them work it out, they will in time spawn, unless they seriously arnt ment for each other, but i'd imagine if theyve been housed in the same tank for over 24 hours and no serious problems, you'll be fine to let them be together till they spawn.