Vertical floating

Question
I have a Betta fish that I received almost 4 years ago at Christmas.  Recently he has been standing vertically as opposed to horizontally.  I have a large clear vase with marbels at the bottom and a peace lily planted through the top.  He sleeps within the roots  of the plant.  I feed him 2 or 3 times a week and change his water when necessary.  I alternate 2 sets of vases so that while he is in one the other is curing for  him.  I realize that a 4 to 5 year Betta is an old Betta but everything else about him seems to be fine.  Is there a reason that he is standing vertically ?

Answer
Hi Tony;

He is a very old little fella indeed! You've done a great job caring for him all this time. I think his body is just failing and is weaker now. He just can't hold his equilibrium in the water as well as he used to. If he seems to start having trouble getting to the top for air, lower the water level so he doesn't have to struggle so hard to get to the top. That happens sometimes with older bettas too. There is really nothing more you can do except to keep up the good care you have already given him.

Followups welcome

At Your Service;
Chris Robbins