Beta fish staying at top of tank!

Hi guys I am new to fish and bought a beta fish he is in a 3 gallon glass tank with heater and filter. The water temp is 82 degrees F and the filter seems to be working fine. Had the water tested and cycled the tank a week before I put him in and the water conditions were perfect. However a week later had the water tested and and the ammonia level was too high. (They said it was probably from left over food in the tank) The fish store told me to do a 50% water change so I did. But he is still hanging at the top of the tank and not really swimming around he just goes from one area of the top of the tank to a different area at the top of the tank and I’m completely lost at what I’m doing wrong or what’s wrong with him. He’s not bloated or anything like that just seems to always be at the top of the tank HELP PLEASE

I am no fish expert but have some bettas. He may be adjusting to his new home, mine often sit in the plants on top of the water and sleep. Maybe lower temperature to 79-80. I've used bettafix and API if I get worried, may not help but makes me feel better ☺ They are pretty chill fish but if he starts to show labored breathing, then he may be sick. Mine died like that from my female stressing him out. Poor guy.

If your aim was to have a cycled tank (which could be tricky in only 3 gallons) ,this is the problem. You cannot cycle a tank in a week, this is the cause of the betta's issues. You are going to need to do a "fish in cycle" as toxic ammonia and nitrite will be building up in the water.

• Do a large (50-75%) water change every day for the next few weeks. You will need to dechlorinate the new water and make sure the temperature matches the old water.
• Feed less, one feed this week, two next week, three the week after up until six times in the sixth week which can continue.
• Buy live plants, floating like salvinia or frog bit are best.
• Get a test kit to check your own water quality, the API master freshwater test kit is good for beginners. Test daily and change the water every time the ammonia or nitrite is above zero.
• Add bottled beneficial bacteria ( such as safe start plus) at each water change.

These measures will reduce the ammonia and nitrite in the water to help the fish whilst the tank cycles.