Fluval 25 Watt Compact Aquarium Heater - 25 L (6.6 US gal.)
YukiHalu Small Submersible Aquarium Heater, Adjustable Mini Fish Tank Heater 25W 50W 100W 200W 300W with External Temperature Controller, LED Display, Used for 5/10/20/40/60 Gallons (25 Watts) : Amazon.ca: Pet Supplies
Nano Aquarium Heater 25 watt - Aqua-World
Marina Submersible Heater for Aquarium, Mini, 25-watt : Amazon.ca: Pet Supplies
25W Smart Mini Aquarium Heater, Betta Fish Tank Heater Thermostat Warmer Submersible Anti-Explosion/Energy-efficient Water Temp Controller | Walmart Canada
Penn-Plax Cascade Heat 7-Inch Aquarium Heater 25 Watt for 5 Gallon Tanks : Amazon.ca: Pet Supplies