Planted Tank Guru
Join Date: Nov 2009
Location: Missouri united states
Two weeks minimum IMHO
Do note that the amount of bacteria in donor tank will only ever be as much as is needed for present fish or fishes in donor tank.
I see only a betta in donor tank,so would not get too wild with stocking the new tank with fishes, but rather do it slowly a few small fish at a time ,while keeping and eye out for ammonia level's other than zero.
Is good that you have a donor tank with already established bacterial colony,just can't suddenly add a dozen fishes to new tank.
Need to let the bacteria multiply a few small fish at a time.
Once bacterial colony is established it can multiply fairly quickly (days), but not quick enough to allow too many fishes at one go.
Would be different if donor tank had fairly large fish population.
Lot's of plant's can help also.