Well, it’s been a long time since I visited the forum, the pond and fish have been doing very well up to now. One of my prized Koi has been acting funny, he may be dying. We returned from vacation and found he is not eating and has isolated himself from the rest of the group. He seems to be swimming on his side and can’t seem to straighten up.
I am wondering what to do, do I euthanize him or try to being him back to health?

Hello Sesco, Sorry to hear. I wouldn't be so fast to put him down. Wait for Robyn to post. I've heard of similar symptoms in gold fish; cured with peas, or popping out the center of them if I remember right.

Since we don't know. Isolating is probably not a bad idea; however, knowing Koi need lots of water, I have no idea what's required for a medication tank so to speak.

Is he bloated at all, scales sticking out like a pine cone?

it's really hard to tell, since he like to be in the deep end 4' deep and hides behind a large rock. He is also a black and orange stripe so very hard to distinguish any type of deformation. he may have been inbreed too much and is a weakling, I have had him for about 2 years and he is about 17 inches and is pretty fat. I tried to take a photo of him but he just doesn't like to pose. I hope I can save him but I hate to see him suffer.

I'm sorry about your koi. You may never know what is wrong with him. You also cannot know when he might die. I've had fish with various problems where they couldn't swim correctly live like that for weeks, months, and even a year. I had an orfe who literally laid on his side and upside down on the bottom for almost a year. I've also had fish lay around or seem sick only to recover on their own and be fine later. The koi could just be feeling under the weather or maybe tired from a visit by a predator. Quarantine treatment will only help if you know what to treat for (a correct diagnosis) and have a smaller pond of at least 100 gallons for a 17" koi. I tend to just leave my fish be, sort of survival of the fittest mostly because I don't have the time and space to devote to all the fish who have various problems. Last week, I found a goldfish on the ground (thanks to the raccoon), went to toss her away, and she breathed. She had a huge bite wound on the face that I thought was fatal but I put her back in the pond. She couldn't swim. When I came home, I went to find her body assuming she'd be dead and couldn't find her. This week, she's back swimming with the other goldfish and eating. So, you never know. If you do decide to euthanize him, I've never personally done that but, because of his size, you would probably need to use an overdose of anesthesia which you'd probably have to get from a fish vet (a rare breed). If you decide to treat him, try pond salt, MelaFix, and maybe antibiotics (if in quarantine).

Peas can be used to treat buoyancy problems if they are digestive in nature. Boil frozen peas and remove the skins before feeding. It doesn't sound like your koi has that. It's more common with goldfish.

I recently had the same problem with a koi and goldfish. My water was very out of balance. I knew that. The owner of a pond store had had the issue also. She had me to treat the pond for parasites.Do you regularily put bacteria into your pond ? We were having to clean out filters because of algae so the "good" bacteria could not increase.It has been about three months of checking water levels of ph , salt and ammonia, and adding bacteria every week and the water is crystal clear. I also added an aerator./ You might also take the koi out and try a salt bath treatment for a few minutes.... for parasites, then back into pond.
karen

It's been over two weeks since I posted my sick koi and he is still in the deep end I see him as he repositions himself but very little activity. My pond is 2400 gal and 4' deep where he is hidding. I can't reach him and I really don't want to poke around and injure him. I guess if he is going to go then let fate take it's place.

I'm sorry about your sick koi. I had an orfe that lay on the bottom for some 8 months before dying. I don't know how he didn't starve to death.

well, he finally floated to the top and I examined him very carefully and could not find anything wrong with him externally. I am heart broken that he lived so long in that condition and could not recover. i wish I could of done something for him. :( :(

I am soooo sorry for your loss. I had one die with no signs of anything on him and I felt bad that I could not put him out of his misery you feel pretty helpless but fish are some of the strangest creatures I have ever dealt with. You did well by him I am sure.

I'm sorry about your koi.