Moving goldfish into a new tank

I have a temporary ten gallon tank for when I ship fish in the mail. I have a 55 gallon that is not going to be up for at least 2 months, probably, can't do anything about it.
My goldfish is currently in a 40 gallon with the rest of the fish and she has been fine but doesn't look too well in the tank, it feels like it's too big for her? Like she isn't used to all that space and she just sits. No health issues, perfectly fine. I want to know if I can move her to the ten gallon for a little bit (Upkeep on water changes obviously) and THEN move her into t he 55 gallon and see how she does. If she doesn't do good with the 55 I will give her, her own 20 gallon or something. But will the stress of moving from tank to tank make her stressed and die? I don't want to risk that but she looks so so unhappy and unwell, and on the verge of something very bad could happen in the 40. I don't know if I' doing something wrong. The water is fine and again no sick fish. I'm nervous to move her?

 

What other fish are in the tank? When did she move to this tank? Is she sitting all the time?
She should be enjoying a 40 gallon, I don't think any goldfish would volunteer to downsize (unless they have SB issues).

 

Right. She moves fine and eats fine and I thought she had swim bladder for awhile but she was getting better and her tail is high on her body so I think sometimes the front weighs her down. 2 orandas and another butterfly telescope are in the tank (she is a butterfly telescope) She has probably been in the tank for 2 and a half months. She has a hard time seeing. Not sitting all the time but she doesn't sI'm all the time?

If she has swim bladder idk what to do because it has not progressed worse and I've tried before, still don't think she has it though or she would be struggling a lot more.

 

I wouldn't get too worried as long as she gets up to swim and beg for food. She might just be napping when you check on her.

 

I wouldn't get too worried as long as she gets up to swim and beg for food. She might just be napping when you check on her.

So I shouldn't move her to a ten gallon temporarily? And what if she does have swim bladder?

 

I personally wouldn't unless more symptoms arise, as it would probably just cause more stress. Swim bladder issues are sometimes caused by constipation, in which case, feeding boiled, shelled peas might help. Sometimes there's nothing you can do because it's genetic or related to the body shape of the fish. Also there's a possibility her swim bladder has a bacterial infection, but I wouldn't think this was the problem unless her swimming started to become uncontrollable.