Diurnal temperature variations

[seangee]

I was playing with my temperature controller today and noticed it supports day and night temperatures (no I didn't read the manual when I installed it )

I know that the circadian cycle in mammals is influenced by temperature as well as light and assume this would apply to fish too - but I also assume there is not a massive variation in the tropics. So would this be worth doing, and if so how much variation. Just because I can I have set it to 2C lower in the darkness hours, although for the next few weeks its purely academic as I don't expect my heaters to come on at all for a while yet

 

[Colin_T]

water holds its temperature pretty well at night so I wouldn't bother changing it between day and night.

 

[Byron]

If you have the ability to run a temperature difference of just a couple degrees, it probably won't hurt. I recall articles in I think PFK suggesting this a couple years ago. I do not do this, just to be clear. I would need two heaters per tank with different temp settings, both on timers, and that is just too much bother for something that likely is not an issue for the fish. As Colin said, temperatures in the tropical waters have very little variation diurnally or seasonally.

Even though day/night air temperatures do vary be a few degrees, the water temperature is less because of the shade preventing direct sun. Fish remain in the dimmer lit areas, along banks if the river is open to the sun, and these waters remain cooler.

 

[The Lumpfish Guy]

Diurnal temperature fluctuations do occur, but obviously the strength of these vary depending on latitude, altitude and type of waterway ect. You even will get a slight one in your aquarium depending on location and house temp especially if you are in Europe at the moment with the heat waves and no air con. I'm monitoring mine closely as all my thermometers are flashing for too hot, and no way to cool the room.

Diurnal temps in the wild can signal everything from feeding and migrations to reproductive behaviour and depending on the type of water can vary by a high range. Take rock pools for example where in the summer it can vary from 14-16 (UK sea temp) to 20-30 (air temp) depending on isolation time.
Obviously that is an extreme example, but in lake shallows when there is little mixing there can be a high variation between the temperature in the top 2-3m and below.

Most fish are able to tolerate a huge variation in their environment as part of their natural cycle, certainly more than we allow in our tanks (provided they are well maintained)

 

[seangee]

Diurnal temperature fluctuations do occur, but obviously the strength of these vary depending on latitude, altitude and type of waterway ect. You even will get a slight one in your aquarium depending on location and house temp especially if you are in Europe at the moment with the heat waves and no air con. I'm monitoring mine closely as all my thermometers are flashing for too hot, and no way to cool the room.

Yup - changed the setting some weeks ago but nothing to report because my heaters have not come on yet.

I have finally stopped getting the flashing warnings for the community tank which is on the cool side of my house. The nano tank still flashes continuously as it is on the warm side. Bad planning on my part cos that one is usually set at 22 (currently on 26). Right now the community tank does change - it goes up by about 1 degree with the lights on and drops that degree by the next time the lights come on. So its about 25 after the lights have been on and about 24 after they have been off.

 

[The Lumpfish Guy]

Yup - changed the setting some weeks ago but nothing to report because my heaters have not come on yet.

I forgot you're in Berks, I'm up in Glasgow. I imagine we are having the same temperature fun!

 

[seangee]

Not something you expect to hear on this little island but...
Woohoo - we have rain forecast for next week

(With apologies to some of those between Berkshire and Lanarkshire who have seen a bit too much water in the last few weeks)

 

[Colin_T]

LOL, you lot complaining because it's 30C there. Try 46C in the shade
It's so hot the roads melt and the train tracks buckle.

 

[seangee]

LOL, you lot complaining because it's 30C there. Try 46C in the shade
It's so hot the roads melt and the train tracks buckle.

Yeah Colin that is the problem. It did get into the 40s here in the South East. Unfortunately because we live in a cold climate nobody has aircon and our houses are way better insulated than yours - to make sure the heat stays inside.

The temp inside my house goes up by around 5C overnight if I close the windows. It's much cooler now but it will take weeks for the (almost perfectly insulated) wall and ceiling cavities to cool. That's why I am so excited at the prospect of a few days rain. I did grow up in a sub-tropical climate, probably closer to QLD than WA, and was amazed at just how uncomfortable 30 can be when everything is built around making sure the heat stays in.