Sounds like dropsy. Which is really just a symptom, rather than the root cause. Once they have dropsy going on (bloated, scales stick up, eyes bulge), it tends to be too late to fix and it is an internal issue.
See how red the goldfish's gills are? I'd guess ammonia issues affecting the gills. Probably affecting the entire fish's systems, and hence the dropsy as well. Goldfish are hardy in that the ammonia has to be a little higher to poison them than a lot of other fish, but it is still detrimental and over a period of time or at a higher level fatal