Temperature: How low can you *really* go? (Whoops, I made a mistake)

[Friller2009]

need some level of scale here. What I call cold may not match what someone from Australia calls cold which certainly may not match what jjohnwm calls cold or indeed same for room temperature.

Also worth noting that I agree with jjohnwm and my posts on here are talking about having seasonal lows - not keeping tropical fish at constant low temperatures (which I would struggle to do as my fish house gets towards 80 degrees even here in the uk during summer).

Lowest outdoor (water) temp in Sydney I get is 7 Celsius, average of 10/12 C, Indoor unheated tanks lowest 12 C, average 16 C.
I let all my fish experience natural seasons. Feed less in winter, shorten light periods, Feed more in summer, increase light periods. I also cut of heat in summer.

 

[jjohnwm]

Aside from relative opinions of what is meant by "cold" or "warm", another consideration is the goal we have in mind with specific fish. My adult long-term keepers are well into their winter semi-hibernation right now, with tank temperatures dropping towards the 50F/10C mark...and the only reason that is happening so late is that I have been heating their indoor accommodations somewhat, into the 60-65F range, simply because if I fail to do that, their winter cool-down will encompass 8 months! So I am experimenting with providing heat for a period of time after I bring them inside, and with beginning to apply heat somewhat before taking them outdoors in the spring. That sounded like a reasonable plan at first blush...but this past spring it resulted in breeding beginning while they were still indoors, which proved somewhat inconvenient for me.

Fry brought indoors from outside this year were divided between a majority which have been kept heated at 75F and which are unsurprisingly growing faster than the smaller group placed into their parents' cooler tank. I'm not into the breeding of these things to make money, but my LFS is happy to take them in trade so I would like to get them up to saleable size ASAP and get them out of here. I'm not fond of using them as feeders, especially when there are people around who would be happy to have them.

 

[Trouser Cough]

The 6 fx 6’s are heating ur tank more than u think… i run 4 fx5 on a 650gal, and a mag24 pump… no insulation, no other heat source and it stays at 72-76 year round. Tank has cold water auto drip that gets as low as 40 degrees in winter also. With a full lid u could probably remove ur heater all together

I've wondered about that a time or two. I've got a laser thermometer around here somewhere and I'll take readings on inlet and outlet of each to see what their contribution is. Good call. Thanks for pushing my inner OCD freak over the ledge!

 

[Fishman Dave]

I've wondered about that a time or two. I've got a laser thermometer around here somewhere and I'll take readings on inlet and outlet of each to see what their contribution is. Good call. Thanks for pushing my inner OCD freak over the ledge!

This again is a great point, I have two identical 390l tanks stood side by side in the same room. One with 300 w heater on regularly and set to 26 degrees the other with no heater but instead of running air filtration it runs an old inefficient 33w 1800l/hr powerhead used to feed above tank home made filter. This tank uses less electricity, gives me mechanical filtration, and is at a slightly more variable 21 - 23 degrees. I need to experiment though cos if I turn off more individual heaters and use powerheads instead then maybe the room temp would drop which in turn may lower the temp of the unheated tank. It’s about finding that balance for me of how many tanks to heat to keep the room warm, or indeed if it’s cheaper or easier to heat the room ( which to date it’s not).

 

[aliadamm]

My basement fishroom is definitely moving in this direction. I'm down to only two "tropical" tanks, with the rest now experiencing summer/winter temperature variations, down to 60F or even a bit less in winter.

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