Elwynnsolo is right, single tailed and fancies shouldn't be mixed.
The single tailed fish are much faster and will out compete for food and can cause the slower moving fancies stress from their quick movements.
I would just like to add that goldfish shouldn't be released into rivers or streams. They should be re-homed, to someone with a suitable tank or pond, or perhaps even a botanical or garden centre that can take them in.
It is illegal to release non-native fish into local waters. If you think you live in an area that has native waters, then please check with a governing body or environment agency first!
Although I can appreciate Elwynnsolo if you live in an area that has native waters for goldfish and it was safe for you to release Groucho, I just wanted to put the information there just in case
Do let us know how the fish are doing Barroniom