Best Practices for Introducing New Koi to a Pond

By Ron Boedeker

The biggest question you need to ask yourself when you bring home a new koi is: Is introducing this new fish directly into my pond worth risking the lives of all of the existing fish?

If this question causes you to stop and think, then you need to set up a decent quarantine system (before you bring home a new fish).

Here are several levels of quarantine to pick from. There are no guarantees in the koi world, but the more effort you put into it the better your results will be.

  • Basic - Bring the new koi home; release them in to the pond and hope for the best.
  • Easy - Release them in to an adequate separate container and watch them for a few days. If all looks well, release them in to the pond and hope for the best.
  • Better - Release them in to an adequate separate container. Maintain mid 70s temperature, good filtration, good aeration, get them eating and watch them for at least 3 weeks. If all looks well, release them in to the pond and hope for the best.
  • Best - Release them in to a large well prepared separate quarantine system with all dedicated equipment. Everything should be separate from what is used in the main pond (separate nets, bowls, etc.). Maintain mid 70s temperature, good filtration, good aeration, get them eating and watch them for at least 2 weeks. Do microscope scrapings to check for parasites. If all looks well, then add a fish from your pond to the quarantine tank and watch them for 6 weeks. If all is well after this 8 week total period, release them in to the pond.

The only things that can be done beyond this would be to hold the new fish separately for a full year and for a very valuable koi collection, blood serology testing might be appropriate.