only my butterfly koi have crystals on fins

[Carla Cowart]

I have a pond that is about 1000 gallons with about 8 Koi over a 1 1/2 long and some koi/goldfish mix (by accident). I've had the pond for at least 8 years. It has a liner. Most of the time the water quality is good unless I have a "run" on algae and have to go through all sorts of moves to get rid of it but that doesn't happen often. I've noticed, or thought I noticed, that my oldest butterfly koi/goldfish mix, (about 8 yrs old), seems to have some crystal looking things on her fins. She's only about 10" of so. I also have a butterfly "koi" that's about 8" that I've only had for about 2 months and she seems to have the crystal looking bumps on her fins now. She didn't have them when I got her. It's really hard for me to catch my fish even with a net so I don't have a photo of the crystal bumps on their fins. I can get a photo if it's absolutely necessary for safe treatment but I hate scaring them because it takes awhile to get them to trust me again. My question is why don't my regular koi and other fish have this on them. How can I treat this safely? Should I treat the whole pond or isolate those 2 fish in a different tank and teat them? I have included a photo of my butterfly koi but you can't see the crystals. I've also included a photo of a random beta off the internet that has what looks like my 2 fish have. Thanks for the help.

 

[OrionGirl]

When was the last addition?

It sounds like ich, which is a multi-stage parasite. The bit you can see are the parasite 'eggs', basically, that will drop off and hatch to release more parasites that will infect other fish via their gills. It can be treated, but you will likely need to treat the entire pond. It can easily linger in low levels in seeming healthy fish, because it stays in the gills. If an animal is stressed, it can't fight them off, so you get a bit outbreak. There are lots of treatment methods--but you will be best suited to review and research specifically treating koi. I've dealt with it in tropical tanks, where the best option is salt + heat.

 

[Carla Cowart]

I added the second small butterfly koi about 2 months ago but she was clean when I put her in. Thanks for the information. I will start my research on how to treat a whole pond...uuggg!

 

[OrionGirl]

Ich is much slower in cool water, so that's likely the source of the infection. You can't see it during most of it's life cycle, since it is inside the fish. Quarantine is the only means of addressing it.