Sorry :( Here is some general information..
Water conditioner is not optional.
2 gallons is minimum for keeping a betta healthy long term.
In this size you should do two weekly water changes a week - 50% and 100%. He should be scooped in a little plastic solo type cup and not use a net. New water should be the exact same temp as old water - matched using his in tank thermometer. Water and conditioner should also be premixed (you can use fresh water jugs from the grocery store - rinsed well in hot water but not chems).
Room temp may not be okay, unless your house stays a constant (meaning no swings or peaks) of 80F+ Any swings (like if you let your house drop at night) are hard on him. They can even be lethal. You need a constant unchanging temp between 78-80F. In a 2G you can get a 25w adjustable heater. Make sure any heater you get is tested 24hours in similar size container to make sure it will maintain a constant appropriate temp. You must always use an in tank thermometer to monitor the temp. He must be acclimated to the water water either by floating in a cup inside the already fully warmed water for a hour, or by adjusting the heater to increase no more than 1 degree per hour and 5 degrees per day.
He should be getting two small meals a day, at least a couple at a time and one fast day a week. However, your pellet is low quality which can lead to constipation issues. You should look for a pellet whose first two or three ingredients are whole fish and not fish meal or wheat.