# Minimum water temp?



## Rhinox

I'm considering whether or not I can get away with not heating my 125g tank. The stock is in the sig, with a future planned addition of some syno multipuncs. In the summer time (i.e. now), we keep the temp in the house at 72, and in the winter, we settle for 68. Right now, the tank is at 72 and the fish are doing just fine right now. Its only been a few days though. My sump isn't operational yet, but I know my pump puts out some heat. In ~40g of water, it alone keeps the water at least 10-15 degrees above ambient, so I expect a few degrees increase in my system (~175g of water total). That means even in the winter, the tank should never dip below 70 degrees.

Are there any negative effects of cold water I should look out for, long term or short term?

Will the fish spawn if the water is kept cooler? (I'm looking to raise a couple batches of fry to work out some M:F ratios)

Thanks for the thoughts!


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## GaFishMan1181

To answer your question i would say yes you could get away with 70-72 degrees but your fish would be alot happier if you bought a heater and raise the temp to 78-79.

74 would be the lowest temp i would ever keep a tank at. 68-70 is too low. I have had my fish at 73-74 before and they grew slower and breed less than when my tank is at 78. If you want your fish to thrive i would buy a heater.

*Is your tank in a main living area or in its own room? If its in its own room you could get the tank water up 5-7 degrees by closing the door and ac vents in the summer and opening the ac vents and closing the door in the winter.

Thats the method i use and my tanks stay 77-78 all year long.


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## Rhinox

The tank is in the main living area. I don't have a good reason to not have a heater, other than that they make me nervous about the inevitible failure. I don't have a heater in the tank just yet because its going in my sump which I haven't set up yet (took 3 days to get my bulkheads into place without leaking :eyeroll: ). I also wanted to see what the tank temp settles at after turning the pump on before going out to buy a new heater, so I know how many watts to get.

I was just reading through some old threads and came across a post where a user suggested that they had better experiences (fewer illnesses) when the water temp was maintained without a heater, anywhere from the high 60's to mid 70's. Just wondering what everyone else thought about maintaining a lower temp.


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## Kanorin

Last winter I tried to be thrifty on my heating bill and let my rooms get pretty cold for a week or two (not sure on the exact temperature, but maybe around 62?). This caused my tank to drop down to around 66 - 68, because I didn't have a high enough wattage on my heater to keep up the temp. The following week 3 of my fish came down with Ich. I then bought a second heater for my tank and successfully treated the ich with meds and salt.

I don't know for sure that the low temperature caused the ich, and I don't know if they still would have gotten it had the temperature decreased much more slowly. But I don't let my tanks get that cold any more. Especially now that I have rarer and more expensive fish in the tank now - it's just not worth it.

But during the summer I do unplug my heaters since the rooms are never below ~74.


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## nick a

FWIW

I've just got 3 tanks left inside the house. All have Mbuna, none has a heater. One has been running continuously since '04 with essentially the original fish it was stocked with. The Cyno. afra Likoma male that is the king of this tank still looks as good as he did when I got him. Besides any additional heat from light fixtures & filters, these tanks are @ room ambient winter thru summer.

If rapid growth or hardcore breeding is your goal, perhaps heat is required. Otherwise, IME, the fish have done quite well and are productive enough in rooms that are climate controlled for human comfort thru the seasons.


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## John27

There is also the disease treatment idea too, one of the best ways to treat for most diseases is heat, can't do that without a heater!

You could also do metal halide lighting :lol:


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## BillD

I kept 3 P.flavus that I got at auction for $1, in a 15 gal unheated tank for 2 years. The temp ranged from 66F in summer to about 74F in fall and spring. They grew to full size and were active at all times. I had no issues with them at all. Breeding was not a concern as they were 3 males. \
I would gues that if you were wanting to breed, a heater would be desirable.


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