I love fancy goldfish... With that said, Colin is correct to some extent. Whenever you hear about an UPSIDE DOWN swim bladder fish - 90% of the time it's a fancy goldfish. Sometimes it's a Betta or Flowerhorn or some other GMO fish... But usually a fancy goldfish. The frequency with which these fish have swimming problems actually makes fancy goldfish keepers the laughingstock of the fish keeping hobby.
The fish are man made genetic mutants. The fancier the fish, the more mutations, the more sensitive and short lived the variety. Jikins for example are nearly impossible to keep. They die so easily and produce 90% junk fish when you try to spawn them.
All fancies have questionable lifespans. They can be hard to keep. And many of them are downright ugly. Even fish from decent breeders like ECR and Zhaos Fancies still get SBD (swim bladder disorder) and other issues more so than normally shaped fish. Also those types of breeders DO inbreed and line breed for certain physical traits.
I love short bodied fish way more than long bodied fish. Ryukins and Yuan Bao/Ingot Orandas are my favorites. Don't load them with food and try to grow them huge, don't put them in deep tanks, and dont subject them to high nitrates, and you likely won't have too many swim bladder issues. I've had a lotta fancies over the years and only 1 or 2 with swim bladder problems.