It's more of an age thing than size. They will start to show pairing behavior between 6 to 9 months of age , start to pair & spawn after that, between 9 and 12 months. I have a zebra that started to spawn real small, not quite half dollar body size. I also have a silver that hasn't paired or spawned, body is the size of a baseball.
That sounds like a good assortment of food, as they get bigger, switch from bbs to brine shrimp. They will grow faster if you kick up the temp, 84-86F is good, & feed more frequently, 3 times a day, but don't over feed. Raising & keeping in warmer temps will make them grow faster, but also shorten their lifespan.
Before you decide to raise a spawn, make sure you have some place to sell them or give them away. Then figure out if you have the time, money & space for at least 200 gallons of tanks to raise them to a sellable size.
Tolak
