Temperature in My Aquariums

Here you can see some of my aquariums with guppies.

Guppies are tropical fish.
Tropical temperature range between 64 to 85 F (18 to 30 C) all year around.
Keeping water temperature without significant daily changes is beneficial for fish.

Conveniently, the temperature in my apartment is between 72 - 76 F all year around, thanks to an automatic heating system :)

The temperature in aquariums on a windowsill is different!

 The outdoor temperature last night was about 50 F (10 C).
Now at 3 pm, the outdoor temperature is 69 F (21 C).

 The temperature in aquariums on the windowsill is 90 F (32 C).
Direct sunlight and heaters located directly under the windowsill contribute to that high temperature!
I keep seed shrimps, snails and other tiny critters along with land moss and some plants in aquariums on the windowsill.
The warmer water, the less oxygen it can hold, making it dangerous for fish!
Most fish would suffocate in 90 F (or warmer) water.
Tiny critters and snails seem to be fine in warm water suitable for algae.

I keep aquariums with fish close to the window, but away from direct sunlight.

The temperature in these aquariums matches the room temperature at 73-74 F (23 C), without need for special aquarium heaters ;)

Have fun and happy aquariums :)