Question
I am sure you have had this question asked a million times.  What do baby koi look like?  Do their colors change?  I have 4 butterfly koi and 4 premium koi, and 2 plan goldfish ( I think).  Lots of babies, but winter is coming and I am worried.  I brought some in a few weeks ago but I don't think they are butterfly koi.Any and all info on the babies will e a great help.  Should I remove goldfish if I want to give butterfly koi a chance to reproduce?  What about premiums? Also pond has many bullfrog tadpoles.  Will they live over the winter or should I bring some of them in too?   So for all the questions.   thanks, Sharon

Answer
Baby koi, unlike goldfish, get their color when still pretty small, some color when they start to look like actual fish.  Their colors, like goldfish, do change but not as profoundly as goldfish.  By the time they are half a foot long, koi have their basic colors but may have sutle changes as they age.  Baby koi have barbels under their mouths.  Goldfish and koi can interbreed but it's rare.  How big are your koi?  If they're under a foot long, they are not likely to have had babies already meaning you would have goldfish babies more likely.  Since you only have two goldfish, they'd have to be male and female to have babies (general 50% probability that any two fish will be the opposite sex).  Koi will breed with goldfish present.  Both koi and goldfish will eat eggs and fry so I would remove eggs or fry when you find them if you want a higher survival rate.  If you want to be sure of which species you have, then you'd have to separate the koi and goldfish.  How deep is your pond and where do you live?  My page on pond winterizing is at http://www.fishpondinfo.com/winter.htm
If your pond is deep enough and has enough bottom oxygen, the bullfrog tadpoles will overwinter outside just fine.  Adult bullfrogs also eat small fish.  Sorry I was a day late answering your question.  Good luck!

Robyn