It's happened to me a few times. You have no way of knowing. Always quarantine new fish if you're planning to add them to your pond with any existing fish. Then if one is sick he won't infect anyone else. But it sounds like these might be the only fish you have? You'll just have to wait and see what happens.

how big is the pond? How many gallons? Did you check the ammonia and pH levels? How many fish are already in there, and how many of them are new? sorry for the questions, but to solve the mystery, they are important.

Cindy

i have now got 4 shubumkins 2 koi and 4 gold fish all bought on the same day and put in the pond the same day the pond holds or has 2110lts of water and did ph test and nitrite all was fine!!!

That happened to me-a goldfish I had bought several weeks before died. But over a month later, the 5 others purchased at the same time are still thriving. In my case, the one that died had always seems a little slower, more shy, etc.

I understand you tested the pH and nitrite, but what about the ammonia levels? You may have had an ammonia spike. Please post the results of the pH test and the ammonia test. The reason I need the actual numbers (and not just "it was fine") is because ammonia is much more toxic at higher pH. A level of ammonia at a low pH may be harmless, but at a higher pH it could be deadly.

ok as requested the ph level is 7.5 and nitrite level was 0 as for the ammonia test i am waiting on my local pet store to get the test kit in.I will post as soon as i know...thanks for the comments folks all info was helpfull and appreciated.... :-)

Do you have city water? I'm watching for an update.

sorry it took so long i got the ammonia test and it tested at 0.0mg/l which the chart says is "fine"..!! the other fish are doing great they are getting bigger too..so im guessing that i was just unlucky and bought a ill fish to start with..but thanks for you help none the less.......ta!

Along with Cindy's information, and since the water chemistry checked out okay.
If your fish were breeding the Shubunkin could have been a female that was run ragged by the males chasing her and she just pegged out.
Some fish die sooner than others, just like people!

You have enough room in the pond [558 US gallons approx,or 464 Imperial gallons] for the number of fish you have.
"Horton"