Warming Up A 2.5 Gal

[injektion]

how should i do it? the lowest wattage heater i can find are 25w but they are as tall as my tank. he's built a bubble nest under an indian almond leaf so i think he's ok with the water?

 

[Truck]

http/www.aquaessentials.co.uk/index.php?...qpf8p0drtmkesm2

http/www.aquaessentials.co.uk/index.php?...qpf8p0drtmkesm2

they're very good heaters, i have one in my tank and are safe under the substrate