We are now into the middle of September so temperatures are often a little inconsistent at this time of year – sometimes we get that lovely late summer warmth and other years autumn starts early with a cooler period (perhaps before it warms up, briefly, again). This can play havoc with your Goldfish as they are warmed and cooled and back again over a few days. Therefore it is probably worth getting the heaters out, albeit set at a low level to ensure there is a “floor” to the temperatures your Goldfish experience. That floor might vary considerably, depending on the variety, size and age of your fish, and your plans for them in the coming weeks and months, between say 12C and 18C but by looking to keep the temperatures reasonably stable they can continue to do well even though the peak growing season has now past.
Any young fish that are not yet large enough to go through the winter will need warmer temperatures now and for longer whereas adult singletails that are not going to be used for shows may well be in ponds and less susceptible to temperature variation as the body of water will be larger and not likely to vary greatly day by day.
For those young fish, or those being shown, temperatures can make a lot of difference to appetite and therefore colour and activity levels so we can help them along with careful management.
Once the fish are back from the shows or are considered large enough for the winter then of course different parameters come into play, which is a subject we will come back to later in the year.