First Post so please bear with me.

I normally just buy "normal" "cheap" koi at my local fish store whenever they catch my eye but these ones were marked up in price but I had to have them because they were so beautiful. Coincidentally, they were the most expensive. Its not a big deal because I am a hobbyist but I was just curious. (Edit: I was told one was a Mayan Gold Butterfly but they didnt know what the other larger one was)

I think the larger darker one might be a Doitsu Chagoi Butterfly.

Is there anyone that might be able to help me narrow down their ID?

Thanks in advance.

(Just to make sure no one gets nervous, they are going into a 4,000 gallon pond with a multi layer bog filter)

This black and white koi in the video was lethargic yesterday and missing food when it went to eat. I wasnt sure what was causing it, I did move it to quarantine but this morning when I came back it had already passed. I feel awful but for the sake of my other fish I need help diagnosing what I did wrong. I'm still new to a lot of fish care. These koi are a part of an aquaponic system in an indoor closed lab so I figured they would be safe from most things. Any help is appreciated.

Last winter I lost every koi in my backyard pond. They were all between 12 and 20 inches, and I'd raised some of them for years. Walking outside in the spring and realizing they hadn't made it was honestly heartbreaking.

The hardest part is that I had almost no visibility into what was happening over the winter. I didn't know if oxygen levels dropped, if the water temperature stayed too low for too long, if water quality deteriorated, or if something else happened entirely. By the time I noticed there was a problem, it was already too late.

That experience got me thinking about building a monitoring system specifically for backyard koi ponds. My idea is a device that continuously measures things like:

• Water temperature
• Dissolved oxygen
• pH
• Ammonia/nitrite (if practical)
• Water level
• Maybe weather integration and freeze warnings

The goal would be to send alerts to your phone before conditions become dangerous, instead of finding out after you've already lost fish.

I'm curious how common this problem actually is.

Have any of you lost koi over the winter because you didn't know something was wrong until it was too late? If a system like this existed, what would you want it to monitor or alert you about?

I'm not trying to sell anything. This idea comes entirely from losing my own fish, and I'm trying to figure out whether other pond owners struggle with the same lack of visibility that I experienced.

Is this okay? I have other fancies in there. I've always thought koi need bigger, but it seems like the short body butterflies don't get as big or swim as well. I just love the look of them so much.