Some basic water temperature rules

[Joshaeus]

Are there any such rules I can use to estimate water temperatures? Here's an example; this year I am keeping two species outside, one of which is the Persian killifish, Aphanius mento (hardy to anything above freezing). If the temperature drops to 32 on a given night, will the water garden (a 20 gallon above ground one) stay warm enough for the fish, or should I pull them inside when such temperatures threaten? Thanks

 

[sissy]

How big are these fish for that sized tank .I have seen some wrap tanks in bubble wrap insulation .That is what I do for some of my flower pots outside

 

[Stephen Noble]

I am not sure what you mean about estimating water temperatures. Are you trying to figure out something like if the air temperature is estimated to drop to 32 degrees Fahrenheit (0 Celsius) from 0200 to 0700 hrs (2:00-7:00 Am) and my water temperature is X at 0200, what will the water temperature be at 0700?
I wouldn't move the fish around unless it is an absolute last resort. For a really cold night, consider laying a Styrofoam cover over the container and use bubble wrap as sissy suggested. I suppose you could also try to find a very low wattage pond heater that will kick on at 35F (1.6C). Most are designed to cycle on at that temperature. The down side to using one of those is excessive heat. I once used one in a porch pond for a winter season and because of the small container size, it really heated the water during the heat cycle. What other fish do you have in the container? What about plants?

 

[addy1]

20 gallon above ground? in the temperatures that are happening my guess is that pond will freeze solid. Esp if you are zone 5

 

[MitchM]

Basic temperature rules
-Eliminate evaporation for more stable water temperature
-Water is denser than air so will be slower to change temperature.
-Smaller bodies of water change temperature more quickly than larger bodies of water.

Buy a water temperature thermometer and know the limits of the fish species you are caring for.

.

 

[Joshaeus]

i am in zone 5, so the fish will have to come in eventually...I'm just trying to figure out when. Thanks