AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks… on July 20, 2026 July 22, 2026 Manufacturer : AquaMiracle. Manufacturer: AquaMiracle. SUPER MINI SIZE This small aquarium heater is thumb size – only 2.36 (6cm) in length. Great for nano tanks / betta tanks. Takes up less space, easy to hide, but in full power!