In May last year I created my first pond and there was a lot of spawning activity right away. Then there were offspring. Several of the fish were black and this year two of them changed to orange. But 3 of the new fry were multi-colored... speckled orange, black and white. I do have some shubunkins that are multi-colored. However, one of the new fish has developed a strange fin (he's now about 2 inches). It is very much larger than the fin on the other side. I introduced two small butterfly koi last year ... but never saw them spawning. And I read today that koi don't spawn until they are 3 years old. I'm pretty sure my koi are not that old. Has anyone seen this before ? Is this just a mutation ? He doesn't seem hampered by this abnormality... swims fine, eats heartily. I guess I should just ignore it... but it is so strange.