Help!
I have two fantail goldfish, I have had them for roughly a month and yesterday(before I cleaned their tank) one of them started sinking to the bottom of the tank and just lying there upside down. It just stays there without moving (all you can see is the lips and eyes moving around) for a few minutes then swims aroung and then does the same again .I am worried that he is dying-does anyone know what might be wrong with him? If yes, what shall I do?
Please help

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