A separate quarantine tank is a must-tool for koi hobbyists.
It is possible that newly purchased koi still carry parasites, bacteria, fungus etc., even though we did our best to eliminate them. Also, if they are shipped to you in a box, they are usually extremely stressed and exhausted. It is important to provide them a nice surrounding so that they can recover from their journey quickly. Even if you bought from a trusted wholesale koi supplier you’ve purchased from for years, you should still quarantine.
We strongly recommend to every one of our customers the quarantining of each new koi.
Keeping and treating new koi fish in a separate quarantine tank for 21 days is the best way to decrease the risk of disease,
as well as giving them the chance to rest and recover before introducing them to your main pond.