About a month ago, my little zebra danio graduated from the nursery tank and moved into the big fish tank with all the grownup fish. It had taken him about 4 months to reach 1-inch long, with most of that time spent in various small tanks and containers, before he went into the magic nursery.
Today, my two baby peppered corydora catfish (Corydoras paleatus) had their own graduation day, moving out of the magic nursery and into the big 38-gallon tank where their parents live. It took these two only about 6 or 7 weeks to reach the 1-inch length.
Here’s one of the young corydoras, exploring the new big tank. Before releasing them into the big tank, they spent some time floating in a cup at the top of the tank, to get accustomed to the new temperature. You can see the two of them, along with a baby snail stowaway: