No, it is not normal behavior. They are pretty active fish and only lay at the bottom for long periods of time if something is wrong. However, it is normal for them to rest on the bottom for a little bit. Sometimes they also rest by floating at the surface BUT if that is all they do, then yes - something is not right someplace.
1) how big is the tank
2) Is there a filter
3) how often and how much are the ater changes
4) tank mates
5) so you use water conditioner?
He's been fighting with his own reflection almost nonstop for the past 2 days
It's possible if he has been doing it almost non stop. Does the tank have a light on? If there are no live plants, leave the light off and see if he gets better. I have one guy that did that because with the light on, he could see his reflection and would flare at it non stop. If I keep the light off, he still gets light from the window but he can;t see his reflection as much so no more flaring.
It could also be a water quality issue -