Betta Fish Hanging Around The Heater

HI I recently got a new Betta fish called Violet. When I first got him at first hung around the bottom, but 20 mins later he was swimming around just fine. I fed him and all was good. The next day he was just curled up around the heater, I was wondering if that is normal or not?

Ps I have a 16 L tank and he is the only one in there.

 

What is the temperature? Is it filtered? Parameters? To me it seems he might be cold bettas need 25-26°

 

The temperature is about 26 degrees Celsius, and yes it is filtered. I took it for a water test yesterday when I got him and everything was perfect. Sorry for not much information.

 

Well if everything's fine he could just be exploring you said you just got him right?

 

Yes and thanks for the help.