I have had spawns start the second the breeders were added to the spawning tank.....and the longest took about 2 weeks....
In one of my outside spawns in the 5gal buckets I use-teaming with live food-mainly mosquito larva-the two females I placed in the bucket fed on the larva for 2 days and then I placed the male (
he had been feeding on larva too)-the second he hit the water the females demanded to spawn....and they did within 30min.....one right after the other for several hours....massive amount of eggs.....he didn't even build a bubble nest until the spawning was completed-he just let the eggs float at first......here are some pics and the story......
http://www.bettafish.com/showthread.php?t=47192