At the time of The Flood it was decided that the koi deserved their own ark.
It had to be towed behind the main ark. On a very long rope. They needed the protection of their ark but also deserved some freedom.
The koi would sometimes go off on a little adventure and when they came back they would tell Noah where they'd been and what they'd done.
Noah looked forward to this and day after day there was a new story for him.
Noah was very pleased he'd given them their very own ark.
He thought that this was probably the very first multi-story carp ark.