Help...Bloated only at night with lighter face

[oddy1234]

Hello, I have had my double fined Betta for about 6 months now, and this is the first Betta I have ever had. He has been doing okay until now. Housing
What size is your tank? 2.5g
What temperature is your tank? 78
Does your tank have a filter? Not anymore due to it making him fly around the tank. Can anyone recommend one that would work for the double fin betta?
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? None

Food
What type of food do you feed your betta fish? Betta pellets and once every three days frozen brine shrimp.
How often do you feed your betta fish?I feed twice a day 2 - 3 pellets

Maintenance
How often do you perform a water change? 2 - 3 times a week. 50, 75, 50. Every other week the 75% is a one hundred
What percentage of the water do you change when you perform a water change? See above question
What type of additives do you add to the water when you perform a water change? Just the water treatment one.

Water Parameters:
Have you tested your water? If so, what are the following parameters? NO

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? He is super bloated, and his face turns grayish white. This only happens at night.
How has your betta fish's behavior changed? When he is bloated and/or white he is slow and does not eat.
When did you start noticing the symptoms? 4 days ago
Have you started treating your fish? If so, how? I have not fed him since Monday morning, I JUST did a 100% change and added two tsps of epson salt.
Does your fish have any history of being ill?no
How old is your fish (approximately)? 6 months

The really weird thing is that I go to bed at 11:30pm my husband comes home at around 2am from work. When I go to bed he is fine super active and happy bubble nesting away. When my husband comes home he is bloated and white faced. This is how it has happened. Monday morning at 5 am I noticed he was HUGE. I stopped feeding him. When I called my husband at 12 he said he looked perfectly normal. Tuesday evening my husband said he was very white in the face but no bloating when he got home at 2am. When I woke up at 5am he was normal. Last night my husband said he was huge again. Big and bloated and whitish gray in the face. When I woke up at 5 am he was once again normal. Nothing has changed except that I put a heater in the tank. I don't see oil build up from it though. I have never seen my Betta poop, I swear he does it when I turn my back. I mean NEVER. I see poop when I clean his tank, but tonight when I cleaned it I didn't see anything because it was 100% changed and I was straining the rocks. Please help I want him to be happy.

[Hassled]

Odd that it only happens at night, do you feed him more pellets at night?

Might want to try a day, to a couple days, of fasting him.

[oddy1234]

I have not fed him since Sunday evening.

[oddy1234]

Is it normal for him to have red lines down his gills. He looks like he is breathing hard. He is starting to bloat right now.