Hi Scribbles welcome to Fish Lore
I'm really sorry your fish aren't feeling well. Guppys are so pretty. I hope to have some one day.
Since they're new it's possible your fish were ill when you got them.
It's also possible your fish are feeling the effects of a cycling tank. Any amount of ammonia can make your fish ill especially since they're probably stressed from the move.
How often are you changing the water? What is your
nitrite reading and what are you using to test the water?
What water conditioner are you using?
Since you have ammonia readings, I'd go ahead and do a 50%
water change.
I'm sorry for all the questions, the answers will help the members help you.
Good luck.