Is he dying?

[appstate]

I recently purchased a new betta, 3 days ago.

All the tests came out normal, I use water conditioner and its a 1.5 gallon tank so have a desk lamp shining on him to keep it warm. Im going out tomorrow to pick up a thermometer to gauge the water temp, but the room is 72-75 so i know he's just a little bit above that. I have a mini heater coming at the end of the week thats supposed to raise te temp 3-5 degrees which should keep it at 78.

So yesterday and the day before he was fine, swimming around, playing in the plants, and when i left for class he wasnt swimming quickly but he was still dong rounds around the tank. About an hour or so ago, when i got back home, he's "floating" near the top with his "nose" stuck to the surface, and he'sgone vertical. he's very still, but his gills and his pectoral fins are moving rhythmiclly. He'll stay like this for a few mintues, then move his fins for maybe 60-90 seconds, then go back to his position. Is he dying? Does anyone know the causes of this? what can i do?