Black Look & Mini Size to Hide Easily: The 20-watt Betta heater with a 4" long x 1" height heating element design takes up very little space, which could effortlessly fit into about 1-5 gallon ...

FEDOUR 10W Super Mini USB Aquarium Heater, Small Adjustable Heater with External Controller for 1-3Gallon Small Fish Tank, Nano Fish Tank Heater, Betta Heater for Fish Bowls IBAY 10 ratings ...

The USB Mini Aquarium is designed to be more than just a decorative piece. It includes a water heater, an oxygen pump, and LED lights, all of which are powered by your USB port.

Mini-aquariums can do well with 25 watts and 36-inch aquariums need 200 watts. ... An immersible heater lies above the aquarium's water line while the submersible can be placed completely underwater.