# Low temperatures and fish



## niko (Jan 28, 2004)

Well, yesterday I forgot the window of my fish room open for about 13 hours. My tanks do not have heaters because I have a dehumidifier which maintains the temperature of the room right at 80 at all times. 

The room temperature had fallen to about 50 degrees. The tanks that were above chest high were fine - water was cold but not as cold as the tanks lower than that. And of course the coldest water was in the tanks on the floor.

I write this because of a peculiar observation that not everybody may know. Tropical fish seem to fall in a kind of stupor when the temperature is too low. They do not die but do not move and could assume any position fooling you into thinking they are dead. Very little or no movement when touched. But the colors do not fade. Apparently the fish can endure such forced extreme low temperatures for many hours.

Some fish seem to be much more sensitive to low temperature - Corydoras and Rasboras are a good example. Gobies and Endlers are pretty resistant. 

My mistake got worst when after plugging in many heaters I went to bed only to wake up to find out that the circuit braker had tripped. The fish room had been cold for about 20 hours when I finally got things right. Even with such extreme timeline only the Cories in one tank on the floor took a hard hit. All the rest of the fish have resumed their normal behaviour. 

--Nikolay


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## fishyjoe24 (May 18, 2010)

time for you to get a gfci installed... and no one can have enough heaters.. that why I like to up size on heaters, and always like to have a spare laying around or two heaters in the tank, if one goes bad or out the other one is still heating the tank.... 

one question though, what was a window doing open in 20-30 degree weather?


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## digital_gods (Apr 23, 2010)

Could the lower temperatures be used to our advantage by reducing the amount of loss during shipping/transportation? Does this put the fish in a hibernation state?

Speaking about cold, is there any plants that have issues with coldness when shipping?


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## niko (Jan 28, 2004)

Gfrc or not if stupid niko leaves the window open forever and never even bothers to look at his fish that's what's going to happen.

After this I realized that during shipping in winter fish are probably getting close to some kind of hybernation. The way I ship is with heat packs and insulation. But I always thought that the temperature dropped down to like 65 anyway at some point. Now I know that most fish will actually be fine at 65 for up to 36 hours for sure, just slow and "sleepy".

I really don't think plants have issue with lower temperatures. I've left moist plants in a plastic bag in my garage for weeks on end. 40 degrees is about as low as it gets there. As long as they don't dry they last literally for many weeks. But there should not be water in which they are soaking. I've never seen a stem plant rot or anything. No plant has stood out as sensitive to lower temperature.

--Nikolay


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## wkndracer (Mar 23, 2008)

Knowing this is an older thread I thought this link would still be of interest to any pulling it up.
http://www.angelsplus.com/ArticleAquariumTemp.htm

I have 'stored' adult angels in the mid 60's range during the Florida short winter season to no ill affect after reading Steve's article. Did two months at 64-66°F with 2 adult females feeding only lightly twice a week. then the house temperature rose and at 70-74° F activity increased to near normal. I can remember going into panics when a heater failed and the temperature dropped below 80°F LOL running to the LFS to buy whatever they had at any price.:fish:


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## fishyjoe24 (May 18, 2010)

nice article thanks racer...


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## Virc003 (Aug 18, 2011)

That sounds like a story I was told about a salamander my ecology professor put in his fridge. He forgot about it until 3 months later. To his surprise, it survived with only a little water and some moss in a plastic bag. Now I'm not saying salamanders and fish are one in the same, but both are ectotherms and, amazingly, have their ways of dealing with relatively harsh temperatures.


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## Silvering (Jun 10, 2011)

You mean all those expensive heaters aren't really necessary? Drat, I just bought two of them. 

As winter seems likely to be a doozy this year it is good info to have. I suspect most fishkeepers with tanks in their primary living spaces will want to keep the fish warmer so that they can watch their antics rather than allowing things to cool down too much, though.


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## ObiQuiet (Oct 9, 2009)

Silvering said:


> You mean all those expensive heaters aren't really necessary?


Oh, I thought they were to keep me comfortable when I have to put my hands in the tank.


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## fishyjoe24 (May 18, 2010)

ObiQuiet said:


> Oh, I thought they were to keep me comfortable when I have to put my hands in the tank.


X2.. I have arthritis in my family genes... and already have it and I'm only 29... don't get me start about winter and it being cold, and sticking hands in cold water.........:twitch::tape2:

so when I had discus, I didn't need those titium heaters for them during the winter.:twitch: um 25- 300.00 each many I did....


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## Zapins (Jul 28, 2004)

Just want to mention that not every tropical fish tolerates low temperatures well. I just lost my entire colony of African multies (60+) to a power outage along with all my kribs. The temperature went down to 55F for about 2-3 days. The African cichlids in particular make sense as very sensitive fish since they come from rift lakes that are so massive that they almost never fluctuate in temperature or conditions. It seems as if the stability of their natural habitat makes them more sensitive just like salt water tropical fish. My guppies were just fine though. Also my angels were alright too, but I think they were ok because they were in the 180g tank which was set at 83F - it must have cooled a lot slower then the other 40 and 55g tanks.


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## Silvering (Jun 10, 2011)

I'm starting to think maybe I should invest in some kind of generator or kerosene heater just in case - I have about $200 worth of Africans myself, and I don't know what I'd do with them if we lost power for days. :-?

We do have a charcoal grill, maybe I'd heat up some rocks and float them in a bucket in the tank. Presuming I could dig the grill out of the snow first!

@fishyjoe - have you tried pond gloves? I've got a pair for when I don't want to get my arms wet. They're long enough that I stay dry even messing around at substrate level in my 55g.


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## Virc003 (Aug 18, 2011)

In my post earlier, I did say relatively harsh temperatures. Meaning relative to their local environment, not the environment we've relocated them to.

To add to what Zapins said, glass is not a good insulator when compared to the dirt and the warmth provided by the earth. So, variables that keep the fish alive in the natural habitat during cold weather are eliminated.


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