I have had my tank about a month now and my two fish that I moved into the new tank have been fine (The move from a 15L to a 190L)
After about 2 and a half weeks I bought another Red Cap (goldfish) he was fine for the first 4 days but after this he suddenly became very lethargic and VERY bloated. He just sat on the bottom.
It didn't look like dropsy, nor septacemia, and I put him in a small isolation tank, after the 7th day he'd died (upsetting)
I have no idea why
All the levels seemed ok, slightly high, but nothing outragiously bad
Was this just bad luck
After about 2 and a half weeks I bought another Red Cap (goldfish) he was fine for the first 4 days but after this he suddenly became very lethargic and VERY bloated. He just sat on the bottom.
It didn't look like dropsy, nor septacemia, and I put him in a small isolation tank, after the 7th day he'd died (upsetting)
I have no idea why

All the levels seemed ok, slightly high, but nothing outragiously bad

Was this just bad luck