I lost one of my new koi today

[Shdwdrgn]

This was the first one I found with good yellow coloration this Summer. He was shaping up as a very gorgeous looking fish too! Unfortunately I have not been able to determine a cause of death. I did a dip-strip today, which showed everything normal, but I'll run the full kit on the water tomorrow. There is a bit more stuff floating in the water since I did the change to the filters a couple days ago (still waiting for it all to settle out again), but the water has certainly been in worse shape at times. Also if there were significant issues with the water, I would expect the other fish to be gasping at the surface, or acting lethargic, but everyone else seems perfectly normal. This is the only time since I started my first pond in 2007 that I've ever had a fish just die (although I've had a couple that jumped out of the water). I don't know what to think.

Rest in peace, little guy...

 

[fishin4cars]

Looks to be perfectly healthy, Could be a internal deformity, internal parasite, or other problem that just showed up. Best you can do is watch the other fish for signs of anything, double check your water, and say a little prayer it's a isolated issue. I've just lost a fish like that in the past, Nothing showed up and it just be one fish with no answer. Hopefully that's all it is, Was turning out to be a nice looking koi! Good luck, I hope it's not something that other fish could get.

 

[fishin4cars]

Check the gills, make sure there isn't any gill flukes, It doesn't show the signs but if you lift a gill plate and look carefully at the gills you'll see very small whitish/greyish colored spots on the gills. That's something I just thought of that it MIGHT could be and easy to check for on a newly deceased fish.

 

[baeya]

So sorry for your loss.

 

[Shdwdrgn]

fishin: Nothing that I can see, the gills are a pretty even coloration, but thanks for the suggestion.

 

[fishin4cars]

Guessing the other side looks the same? oxygen level- should be fine. I know your set-up, no, red streaks or slime build up, so i would think your test strips are fairly accuate, little or no ammonia, same for nitrite, just no signs pointing in that direction, not external parasites, Hardness wouldn't effect one fish and even then the biggest problem would be a PH fluctuation, Nitrate? Only one healthy looking fish dying, I have to rule out poison or contamination. Puzzling to say the least!!!

 

[j.w]

Very sad to hear shdwdrgn. Hope none of the others have problems.