fantail sick

Question
i got 4 fantail goldfish and they are staying at the bottom of tank what could be wrong with them

Answer
Hello Felchia-

I'll need some more info before I can help.
What temperature is the water?
What do the fish look like?
Are there any other symptoms?
When was the last water change?
How big is the tank?

Let me know more about the fish and the setup and I will try to help.
-Amber Worman