Jekyll, our CT, has had issues with constipation ever since we bought him, but it seems to be getting worse. It used to be a once in a while thing, but now it's every other week he's constipated. It's now been seven days since he's gone to the bathroom and he's looking bloated. He's in our QT right now with no substrate so I can monitor when he goes and how much and with Epsom salts. For the last week he's been on a diet of very little brine shrimp and nothing else. I tried to get Daphnia, but our LPS is currently out. I've been fasting him for two days now because I know it isn't good to keep feeding a constipated fish, although he acts like he's starving to death

I've been able to manage this issue with him by adjusting his diet and a day or two of fasting every week in the past, but that method no longer seems to work like it once did.
Any thoughts? What can I do different to help this not happen? I normally only feed him soaked pellets and frozen brine shrimp because anything freeze dried seems to make him worse.
Housing
What size is your tank?
He's currently in a one gallon QT
What temperature is your tank?
80
Does your tank have a filter?
No
Does your tank have an air stone or other type of aeration?
No
Is your tank heated?
No
What tank mates does your betta fish live with?
None
Food
What type of food do you feed your betta fish?
Frozen brine shrimp and Omega One pellets
How often do you feed your betta fish?
Once a day - but he's on day two of a fast
Maintenance
How often do you perform a water change?
Right now every day
What percentage of the water do you change when you perform a water change?
100 %
What type of additives do you add to the water when you perform a water change?
API Stress Coat +
Water Parameters:
Have you tested your water? If so, what are the following parameters?
Ammonia:
0
Nitrite:
Nitrate:
pH:
7.8
Hardness:
Alkalinity:
Symptoms and Treatment
How has your betta fish's appearance changed?
He's bloated
How has your betta fish's behavior changed?
He seems fine, swimming and active
When did you start noticing the symptoms?
it's been off and on for months
Have you started treating your fish? If so, how?
On day two of Epsom salts
Does your fish have any history of being ill?
Yes, he gets constipated off and on, has since we got him.
How old is your fish (approximately)?
We've had him for six months, but I have no idea how old he is.