Sounds like you may have brought home something on that fish. Anytime you get new fish, you need to always quarantine it in a separate facility for a while to insure it is healthy before adding it to your pond. A good QT can be built from a kiddy pool or stock tank. QT is more important now than it ever was because Koi Herpes Virus is a fatal disease that can kill every fish you own. It is contagious. Anyway....that's not helping the current situation. You need to contact your local koi club and see if they have a koi health advisor that can come over and help you diagnose your fish and suggest treatment options. Don't salt the pond at this point. Salt can't be used along with some treatments and that may cause problems. To locate a koi club in your area, go to the AKCA (Associated koi clubs of american) web site. They have all of them listed. Good luck! Here is a link that might be useful: AKCA

After a dealing with a Heron situation and a over-feeding situation that led to fish dying ( possible fin rot and stress from being poke at.)--The addition of a $5 bag of solar salt from Menards really did the trick for my fish. Since adding the salt, I haven't lost a fish. Is this something I should be doing each spring? Also Mike , I am in North Aurora-I watch this raggedy a$$ Heron, who look like he had a fish hook was in his beak-stalk my pond--he ducked under a table, squeezed between chairs,do everything like a cat. When we came outside he slowly moved from us--Either this guy is starving or he is a real psycho! The pond has a net and a plastic fence so Psycho left empty beaked. Have you seen this fellow?

Anne: thank you so much. Both me and my fish could use as much of Gods help as we can get. I've prayed myself for him to guide me in my fishes care. Mike: Week ago Sunday I first noticed a red spot behind his head in the first row of scales. Fish took ill following Wednesday but this area was not red that day, was red Friday or Saturday, has now cleared up. Sunday I noted another reddish patch oh his belly a little before his vent. I believe these are small ulcers or body sores. I am hoping it is an electrical shock (as anything biological that causes this is dreadful for ALL my fish). The poor thing knocked the fish tank type heater into the water sometime Friday night and it was only after this I noted the bent tail. It seems like it wants to be more active but also seems like it has no control over its main back fin, all swimming is done with its front fins. I am worried about it not eating as starvation isn't very pleasant and I do have some medicated food I would like to try. Last night I found I can gently raise him to the surface and actually got a few pellets into his mouth,though most were spit right back out. For him to have hit his head he would have to leave the pond. I did have some predator take 3 goldfish 3 months back, perhaps it came back and got hold of him.

I agree with Petco or Petsmart fish.. they stock a small aquarium with koi every so often and all of them die within weeks.. I pleaded with them to change the environment they put them in but I was ignored.. they are also domestic koi they are getting somewhere in the US.. In my other aquarium I have I bought a bunch of neons and the water or fish I bought ended up killing half my fish in my aquarium.. so always have to be careful what fish you add and any water as well.. a quarantine tank is a great thing but most dont have one..