When my fish get sick they go off by themselves; lethargic yes- often times float on their sides-sometimes markings on theskin like ulcers.
Check out a site called koicrisis.com and many other sites tht will come up if you type in koi fish deseases. Over time I have learned alot and often feel like Dr. Doolittle. I have a huge business in Orlando that has fish biologist on staff that I call for help. Also a couple that run a fish farm not far from us have helped. It's definitely a learning process. I'm sure I still have a lot to learn. Carolyn has always been a huge help.
Now I keep fish meds on hand. The quicker you treat them the more chance they have for survival.
Bonnie
