Becuase Agent P used their pond to enter his lair, the O.W.C.A., to avoid lawsuits, made them secret agents. They later came to Perry's rescue while he was trapped in a baby's high chair. When Heinz Doofenshmirtz was putting the stinking bottle of diaper smell into one of his inventions, the koi swooped in and got Perry out of the chair so he could save the day ("Attack of the 50 Foot Sister").
One of them later appeared in the Animal sensitivity seminar but later was carried away by a heron agent due to them being excused by Carl Karl ("La Candace-Cabra").