Good evening Dr. Bob. Can you tell me? I have a outside yard pond with 30 koi in it and only one 3-year-old goldfish. Last spring I was watching the fish and noticed the gold fish spawning and the same day I saw a koi fish spawning. We ended up with around 40 surviving fish . The goldfish died shortly after.

I now would like to only have a koi pond. Since there were no other gold fish to fertilize the gold fish eggs I know they were fertilized by a koi fish so are the fish goldfish or koi? I know how to tell the difference when the fish get bigger by the whiskers. How can I know for sure what kind of fish there are? The new fish are gold or grey or gold and black.