Just wondering, since summer is in full bloom here on the face of the sun (Las Vegas)... I know that goldfish can survive very cold water, but what are their warm water temperature limits? The hospital tank (20 gallons) can get up to 80 degrees and above in just a few days, but our main tank (55 gallons) seems to hold fairly steady at around 77-78 degrees. At what point do I need to start adding ice or ice bottles (which we already keep around for the ferret anyway) to the tanks?

--Roc

According to Rick Hess, goldfish can stand a temp of 95 F or higher if thety are not crowded.

The ideal temp according to Rick is 72-74F. According to Doc Johnson, it is in the high 70s. So your main tank is actually quite "perfect".

and to help with the heat you can add airstones to each tank

The main thing to worry about at higher temperatures is oxygen in the water.

The best way to get oxygen in the water is to agitate the surface. HOB filters will create ripples, and so will air stones. My tanks have been at 78-80 since early May, and I have two HOB filters and an airstone running. The fish are happy so far.

There is also a member here in Houston whose ponds get up to 90 with the fish being fine. Just make sure you have lots of aeration at those temps.

In the winter I usually close my heat vent in the room and the temperature in my room goes down to a stable 65*F. in which Nemo (last winter I didn't have Cynthia) really enjoyed. He was more active than ever! As for the high temp., right now mine is at 78* F so I just do a lot of water changes to aerate the water instead of using an air pump.

77-78 temprature is fine for your gold fish i don't think there will be any problem
here in india our goldfishes do fine even in 107 F (42 C) without any problems If more temperature arise ie 113F or 47C then go for daily 25 to 50% water changes.

Wow 113F!! If the water gets that hot, how hot is the room??

temp generally 116 or more but this temprature not lasts for a long period in every summer season just for 2-3 days max then it starts raining by the way our rooms have acs but in my farm there is no acs where our more than 250 orandas live in cement cisterns and face summers heat very bravely .
in my house i only have 10 orandas.

Ah, well, I came here sort of looking for this kind of answer. We're having a hot one in Los Angeles this year. My 60 gallon tank is not in the sun at all, but is still managing to stay at a constant 82 degrees F. It has lots of circulation and aeration(2 penguin pumps and bubble bars running the entire length of the back) and my goldies are acting fine, but I guess I still worry. Chillers are god awful expensive and take up room I don't have anyway. So, I guess what I'm hearing here is that they should be okay?