Fond of filter engine?

Question
So I've had my Betta fish for whereabouts of a year now; he lives in a 5-gallon tank with a filter, several decorations, no heater as of yet (but a rather large light above the water that seems to be doing a well-enough job for now), and he is the only fish in the tank.
He eats well - usually gets excited and 'dances' when I start to give him food, which is flakes, and bloodworms every few days.
In general, he seems really healthy. (save for mildly tattered Dorsal, Beard and Tail fins from earlier in his life; an extended bout with now-removed plant deco, and another with a net I've since never used on him again)

My problem is that I've noticed he seems to have the odd habit of sitting on the 'engine' of the filter I'm using.
I use a 'Marina Slim Filter S10', and more often than not, the part of the filter that the 'engine' (a big blocky bit right above the suction tube - it has a 'ledge' that sticks out about half an inch) is in sits one to two inches below water level.

What I have observed him doing is 'sitting' on the block-ledge, and gently curling a little, so it looks like he's just sitting down on the block and leaning on the tube; he does this quite often and I'm just not sure if it's bad behavior, or if he just enjoys the gentle vibrations that the engine gives off.


I know that a Betta sitting, clamp-finned, in the back corners of a tank is bad, and usually means illness or depression, but my Betta is often active, fins rarely clamped (and occasionally flaring at me).
Should I be worried about this?

Thanks in advance. :D

Answer
Brittaney,

The light in the tank might help him with the water temp while it is on but when you turn it off, the temp of the water drops and that is not good. He really needs a heater. Chances are he is trying to get heat from the motor of the pump. Another good reason to get the heater. He is trying to tell you that he is cold. They need their water to be at 80 degrees all the time and a desk lamp is not going to do the job. He also does not need the filter at all. Once you get the heater, I would remove the filter. I do not think he is sick so there is no need to worry there.