Betta question

I got my mom a betta from a LFS and he acts different from when I first got mine, but maybe he is just stressed. He has the horizontal lines on the body which I know can signify stress. But my main thing is that the tank is cycled, ammonia and nitrite are 0, nitrate is below 5. It’s a somewhat heavily Planted tank. However, he stays only at the top. I’ve seen him swim through the tank a couple times. He has eaten, so that’s good. However he kind of attacks the top of the water lol idk if he sees his reflection or what but he skids across the top. Lastly, it could just be nothing, my betta does it occasionally, but he seems to float to the top of the water in an unstable way... I don’t know what the disease is called that causes that. I looked up dropsey and he doesn’t have any of the missing scales, no bloated belly, etc. though his gills seem to be working kind of hard. The more I look at him, the worse he looks.

The second picture is him in the middle of attacking the water lol. These pictures are him yesterday; but today he hasn’t left the top of the water. I fear he may have been sick when I bought him.

My pet store bought betta does the same thing - attack the surface of the water. I believe it’s because he sees his own reflection.

I would keep a close eye on him, to make sure he doesn’t develop any diseases.