Help!

[irxshob]

I had just purchased a betta, his name is Samson. The problem I am having is the filter is actually heating the water. He is in a 4 gallon bowl. It is an internal hanging filter. I did a test. With the filter on the water temp went up .7 degrees in 10 minutes. With it off it stayed idle at 79.5 degrees. Could this be a defective filter throwing off heat from the motor? Or is it due to the filter being at a slight angle and not flush against the side of the tank?

 

[pablothebetta]

If anything, I imagine it'd probably be a fault with the filter. Do you have a heater in there?