gold fish & Koi

Question
I had a orange all orange gold fish, then my neighbor gave me an all white Koi, my goldfish turned all white.Why did this happen? & i was wondering how can you tell if a gold fish is pregnet?

Answer
I have seen this happen alot in ponds.  I had a Large Blackmoor in a pond with 10 large, all orange Fantial Goldfish.  The Blackmoor became all orange in around 2 weeks.  They could have changed colour because of sunlight or no sunlight or because the cells in their scales took the the white around them (which is what happened to my blackmoor).  Secondly, goldfish don't get pregnant.  They lay their eggs and then the male fertilizes them.  But they do get very round when they are ready to lay their eggs.

I hope I helped,
James