Betta Bowl Heater | A guide to the Best 3 heaters for Betta bowls

Betta bowl heater in 2.5 gallon tank
This is an example of a Betta bowl heater in a 2 1/2 gallon tank. Notice the heater is tucked underneath the gravel and the only thing you see this black cord. These heaters are so thin they aren't taking up much room at all due to the flat construction.

BettaTherm™ Mini Size Betta Bowl Heater 7.5 Watts For 1 to 3 gallons

BettaTherm™ is completely submersible Mini Size Betta Bowl Heater. Increases water temperature 5 to 10 degrees Fahrenheit over ambient room temperature.

-Mini Size Betta Bowl Heater!
-Now with Thermal Shut Off at 26°C
-Completely submersible (Bury under gravel).
-Increases water temperature 5-10°F over ambient room temperature.
-Fits most fish or Betta bowls.
-Can be used on both glass and acrylic tanks.

right now on eBay

Marina Betta Fish Submersible Heater for Fish Tank Aquarium 8 Watts For 1.5 gallons

Marina Betta Fish Submersible Heater
Marina Betta Heater is an automatic, submersible heater that creates ideal water conditions for bettas to thrive in. The exterior is made of durable polymer, which is more resilient than traditional glass sleeve heaters.

-8-watt submersible fish tank heater for aquariums up to 1.5 gallons (5 L)
-Creates ideal conditions for bettas to live in
-Made of durable polymer, which is tougher than glass
-Easy to install in your betta fish tank; use the suction cups to place on the side of the betta tank
-Automatically reaches set temperature; allowing you to easily maintain your fish aquarium

right now on eBay

Aqueon Fish Tank Mini Heater, 10-watt, Plastic Up to 5 gallons

Aqueon Fish Tank Mini Heater
Aqueon Mini Heater provides warmth to tropical fish. Designed with a shatterproof housing and thermal safety shut-off, this compact and completely submersible mini heater is perfect for desktop aquariums with a minimum size of 2.5 gallons and up to 5 gallons.

-Perfect size heater for Aqeuon Mini Bows and other small aquariums
-Ideal for desktop fish tank aquariums up to 5 gallons
-Features thermal safety shut-off
-Aquarium heater is shatterproof

right now on eBay