Over the last week or two I have noticed 2 of my large koi have been swimming near the top with their mouth open. Both of their fins and tails have white around the edges, almost transluecent. Also they both have a couple white bumps on their forehead and near their mouths, maybe about the size of a half pea. The both seem to eat, just not as much as the other in the tank. I did change over my tank to a larger 300 gallon tank about 6 weeks ago and did lose 1 koi I assume to stress, the others have been going fine. Water quality has been stable for all these months with pH 7.4-7.6, amm 0-0.25, nitrites always 0, and nitrates 40-80. I do salt my tank to 1ppm every month as conditioner. I also have an airstone bubbling away and 2 return downspouts that are constantly draining and splashing the water. i have my pump going on a 15 minute on, 30 minute off cycle and estimate that I am turning the water over around 1.5 - 2 times per hour. My tank isn't over crowded as I only have 7 koi in there all around 12-16" big.
I am at work right now so I don't have any pictures, but I did find an earlier pic online as to what my fish look like, but it didn't give a diagnosis or treatment. Both kois fins and tails look just like this pic. Also some whitening to the edge of their gill plates. My fish don't have the hole on the head, but they do have little white bumps, similar to what you see on the left side gill cover, mine are just on its forehead and around the mouth.
Anyone know what this is or how I can treat it? Right now it is only affecting 2 of the koi but I do see some slight white fin egdes on the other koi that are swimming around more actively, and I don't want anything to spread through my tank. I'll post a couple pics tomorrow when I get back home.
Thanks,
Cory
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