hi, a large koi in our pond has scaling skin and is lethargic. we lost another large koi two weeks ago from an unknown ailment, any ideas what i can use to solve this problem thanks
What is the location of the pond, KH, ammonia, nitrite, temp, fish load, size of pond, number and size of fish? What do you mean by "large"? 10"? 16"? 30"?