People breed them year round
Some breeders post the age of their fish when they sell on aquabid and eBay. I see a lot selling at the 4 month mark.

 

There is no natural breeding season. It's more about the breeder's convenience. Many hobbyists in 4 season areas choose to breed in late spring for heating purposes - by the time temperatures begin to drop, they can rehome the fry and not worry about heating solitary jars.

To my knowledge, those that can sufficiently heat their tanks/jars, breed all year round.

 

Thanks for the confirmation, that's what I wondered if it can be a bit regulated by conditions.