They may be afraid of the plant. My goldfish was the same, try moving it.
What else would you expect them to swim in? Of course Goldfish swim in water.
No
Goldfish are moderately inactive fish. They will spend much of their time just floating or sitting at the bottom.
A damaged swim bladder.
because they are fish
NO. Unless there in ranch
If you recently introduced the plant, then the fish may be unsure or fearful of it. Just as you wouldn't turn your back to someone you don't trust, the goldfish does not want to make itself vulnerable. Chances are that the fish will eventually not feel threatened by the plant and will be comfortable swimming over it.
An upside down goldfish means it has a swim bladder disease. If that disease is detected on your goldfish early, it is treatable with isolation and medicated food. But if the disease is detected too late, the results are irreversible-it is a deadly disease.
Anywhere :)
Freshwater
sometimes if there in the mood
Swim, Eat, Swim, Eat, Poop, Swim, Eat,Poop....