https://www.aquariumcoop.com/collections/lights/products/fluval-nano-aquarium-heater-25watt

[Louise02]

How has this heater worked for your betta tanks?  It seems like it wouldn't be quite warm enough.

 

Fluval 25-Watt Aquarium Heater for Nano Fish Tanks | Mini 25W Heater – Aquarium Co-Op (aquariumcoop.com)

[Lennie]

Tank size and the difference between room temperatures that you keep your home at and the temperature you aim to have plays a big role on heater selection. Providing info on these two might help

[Louise02]

On 3/9/2023 at 1:29 PM, Lennie said:

Tank size and the difference between room temperatures that you keep your home at and the temperature you aim to have plays a big role on heater selection. Providing info on these two might help

2.5 gallon planted tank temporarily contains a betta.  Once our current ich outbreak is under control, it will be a snail tank...maybe someday a shrimp tank.  For now, I have two small heaters in there that, together, keep it at 80*.  When we had the temp down around 74* the poor thing wouldn't even swim.  The ambient temp fluxuates, but is about 70* most of the time.

[Furbs]

I have one in a 10g tank. It’s reading 74ish room temp is is about 70. Heater seems fine as long as you’re okay with the preset temp range 

[Pepere]

I use a 50 watt in a 10 gallon.

 

25 watt in a 2.5 should not pose a problem with ambient temps around 70..

the preset of course limits temp to the preset temp…