I don't know what size tank you have, but you don't want to overload the tank. I personally don't have other fish with my bettas at this time. You can't keep any other bettas with him. He will fight both male and females. I know that you can keep neon tetras with bettas. They are schooling fish, though, so you would need around 6 of them, and again, if your tank isn't big enough, your bio-load will be too much. You might want to consider a snail or some shrimp. I think he would be entertained by those. Hopefully someone with more experience keeping different fish with bettas will weigh in! I know it can be confusing, but you'll figure it out!
*EDIT* I just reread the post and saw that I overlooked the part where you have a five gallon... *facepalm* Sorry! So with a five gallon, you wouldn't have enough space for schooling fish.