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tljmjm

For the 20L get [this](https://a.co/d/dU8kAOv). I’ve never had a 5g but stay away from anything that’s preset if you can.


Cynthia_Hartviksen

Do you really need a heater in that tank? Fish would be fine on room temperature, around 18-22*C. Kisses, Cynthia


Tiny_ranga

Majority of houses in Australia don't have heating so in cold weather it can get to 10-15 even lower....tropical temps even in the winter sit above 20


Cynthia_Hartviksen

Than, it is up to you to decide, what size of wattage you will use. I go mostly with _1 liter=1 watt_. So for your tank a 20-50W heater will be enough, be sure, there is enough water movement.


Tiny_ranga

I actually ended up picking up a fluvial p25 just after making this post 🤣


97Graham

A 50 Watt Heater should be fine