My knowledge on Goldies is not great, does having 9 various types of goldfish in that 5 foot tank mean you need to be overfiltered to cope with the amount of mess from them and do big weekly waterchanges?
The tank is overstocked....i dont over filter, as they really dont cope well with being churned around the tank, but i do need to do large water changes....i have just dropped their heater temp down to 23C to get ready for the colder weather (water changes are not such a big temp shock that way)
Scanning the tank this morning like i always do, and i notice Pea is developing the same thing i lost Joufflu too..... Will be doing a water test shortly, all params were normal last test so i dont know what it is......