The following chart lists the most common
reasons koi die.
1) Poor water quality
33%
2) Parasites
25%
3) Ulcer disease
15%
4) Predators
10%
5) Lack of oxygen
6%
6) Medication overdose
4%
7) Jumping out of water
3%
8) Virus
2%
9) Toxic pesticides
1%
10) Tumor
1%
.
.
From the chart it becomes obvious that if you
can prevent the first three causes of death
you will cut your potential losses by over 70%.
Here is a brief discussion of how to deal
with three of the top causes of death for koi.
Poor
Water Quality ...Parasites...Ulcer
Disease/Bacteria