Can Goldfish live in higher temps?

[Juannie]

Well I've posted a couple of times about my black moor, he had a constant problem with fungus and I've treated him in numerous ways. It had settled for some weeks now, their temp in the tank had been sitting around 26-27 degrees, as soon as I dropped it by a degree on the weekend he's started getting the fungus again. I'm doing water changes regularly, filtration is good and the other 2 fish are fine and happy, can they survive well on higher temps? I know in summer here their tank hits 28-30 degrees and they're pretty tolerant, but as soon as it gets cool he gets this darn fungus again.

[Drumachine09]

Generally, the more elaborate the goldfish, the higher temperatures it will be able to tolerate.

[cocoa_pleco]

agreed, the more elaborate, the higher temp it can have. Fancies often can have higher temp

[GoldLenny]

26-27C is too high even for fancy goldfish. That's up in the high 70'sF to 80F. This is tropical temperatures and too warm for goldfish. While they can handle short term rises to that level, they do best in the low 70's to 74F. Higher temps raise their metabolism which means they will need more food and thus create more waste. Prepare to do more frequent 25% PWC's to keep the water quality from going bad.

Goldfish like and need cooler waters as the cooler waters hold O2 levels better than warmer waters. Since goldfish put out so much CO2 and ammonia during gill function, you should add additional aeration and/or surface agitation to the tank if you will be keeping it at the higher temp, to allow for better gas exchange to keep the CO2 levels down and O2 levels up.

Also, while higher temps will speed up the lifecycle of most parasites, it also causes bacteria to breed better/faster so you could see some bacterial issues.

IMO, it would be better to keep the temp in the low 70's F, (22-24C).

[Drumachine09]

Goldfish can tolerate a high range of temperatures. Black moors can tolerate near freezing temperatures to mid to high 70's.

[Juannie]

Thanks for that. I've had the higher temps in my tanks since I've had these 3fish 4 years ago because the gold coast gets very very hot in summer - the tanks have hit 30degrees indoors & that's even with iced water bottles to cool them down. It doesn't seem to have affected them in anyway. I'm just a bit wary now lowering it because my black moor gets fungus way to quickly when the temp drops even one or two degrees. It's still so warm here in winter we're walking around in shorts & t-shirts!

[Rue]

I've lost several goldfish to the heat in our house during the summer...it's only that hot for a week or two, but it's been enough to kill the fish...

...now that I have them down in the basement, it's a whole 'nother story...

...temp. 68-70 F and they're loving it!