Got up yesterday morning and my fantail goldfish was 'hanging' in the water - head up but completely vertically.
It had been a bit 'off' for a while - would go and hide under the filter but come out when food was about and then swim around normally, and had been doing that for weeks so I sort of came to think of it as her normal behaviour, but last night it was just staying on the bottom, and then this morning doing its hanging impersonation.
I put it in the q tank, and have watched it for a while, but obviously something was wrong - not able to swim, seemed to have trouble reaching the surface so I thought it might be some sort of swimbladder problem.
Anyway, upshot of it all is that I have just had to put it to sleep because it was obviously in distress
It was a great little fish, but fortunately the other two seem fit and well.
My query is, do I need to treat the remaining two for anything - if it was some sort of internal bacteria that caused it - or just keep an eye on them?
By the way, all the water stats/temp etc were fine.