r/Koi

My husband came home with 5 baby koi (1-1.5 inches) from a customer of his who has a beautiful big pond. We do not have a pond, but are obviously now committing to building one. In the meantime, we plan to keep them indoors in a 50 gal aquarium tank. They gave us food and a filter.

1. For initial transition from Tupperware to Tank: do I need to run tap water through filter system for a certain amount of time? What else should I add to the tank water?

2. How long do we have to make a pond happen!?

I get the "you should never keep Koi in a tank" sentiment. This is temporary, I promise!

Thank you.