I started with one goldfish before getting my second. When I got goldfish #2, he was bigger than goldfish #1. I noticed that my goldfish #2 would get "bullied" by #1. #1 would like to push him and when I fed them #2 always would just sit at the bottom of the tank, while #1 ate a lot. #2 became skinnier than #1 and then sadly #2 died. I thought this was because #1 might have just "abused" him and that led to his death, however now my goldfish#1 isn't eating and looks thin. It looked like she was having a hard time breathing. She's in a tank and I have a filter, I'm not sure if it could be ick or something... I don't see any white bumps. But my goldfish is in some kind of distress, please help!:(

Sounds like goldfish #2 had an illness and passed it on to goldfish #1.
If there is no visible signs of illness it could be a bacterial infection.
Your local pet/fish store sell medication to treat illness.

I think you're right, thanks so much for answering my question! I got the medicine yesterday and she looks chipper already!

You're welcome

That's normal. WHen a new goldfish joins the tanl they will starts to fight or the fish #1 nibbles the #2's fin, maybe they just don't get along