I rescued 2 goldfish about 15 months ago. They were teeny. I know now that they are Oranda fancy goldfish.
I rescued them from a pet store that went out of business and left them (and some frogs) in a concrete pond with no pump - full of fast food trash and hardly any water - really disgusting. Later that day I went back to get them. I was surprised to find 2 of these little guys - a red cap and a bronze. At first I had only seen one.
 
I LOVE these fish very much but knew recently that I had to find another home for them because I only have room for a 10 gallon tank. They got very healthy and playful. Plenty of filtration and constant water changes, but they were pushing 3.5 inches with tail and time to move to a bigger home.

Anyway a very kind person offered to take them in his Koi pond and I transferred them yesterday. The hid a little at first but then began swimming around a little - very slowly and cautiously, the bronze one clinging to the side. The red cap was braver. However, something just did not look right to me. They looked so small and fragile in there with the 18 - 24" Koi.

I was worried about them competing for food in the pond as there are about 12 large Koi (18 - 24"), 6 or 7 small koi and some comet goldfish in there and they are so much faster that my little guys.

I realize now that I may have made a mistake. I don't know if they will survive in that environment. I also noticed that the bronze oranda looked like he was having a hard time swimming and his tail looked bent when he reappeared. I wondered if it got bumped by a large koi as the koi are so lively, fast and strong.

I hope I can undo this mistake if in fact it is a mistake.
Can I get some opinions, please. I hope it's not too late to retrieve them if necessary.
If this is the wrong forum to post this question, please direct me to the right one.
 
Thanks very much in advance,
A frantic mom.

I'm not sure on keeping fancy goldfish with koi in a pond... I would have thought koi would be very fast for the fancy varieties.
Perhaps speak to the pond owner about you're concerns and ask how they're getting on

You could always look for someone in the local area who perhaps only keeps fancy goldfish Perhaps look for a local fish keeping society they might be able to help?

As for the bronze goldfish's tail being bent... I believe sometimes fish can have scoliosis (bent spine) so it could possibly be that, not damage from another fish.

But well done for the rescue and all you've done for the fish so far