Housing
What size is your tank? 1 Gallon, currently his only home until I know if he'll get better
What temperature is your tank? ~78 degrees
Does your tank have a filter? Yes, but it's turned off now.
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? Bloodworms, and attempted pellets (he refuses the pellets completely, however)
How often do you feed your betta fish? 1 pellet attempt twice a day, 2 bloodworms if he doesn't eat the pellet and I remove it from the tank.
Maintenance
How often do you perform a water change? Twice weekly, used to be once daily.
What percentage of the water do you change when you perform a water change? 50%
What type of additives do you add to the water when you perform a water change? Jungle water conditioner
Water Parameters:
Have you tested your water? If so, what are the following parameters?
Ammonia: Unknown
Nitrite: Unknown
Nitrate: Unknown
pH: Unknown
Hardness: Unknown
Alkalinity: Unknown
Symptoms and Treatment
How has your betta fish's appearance changed? Seems somewhat duller in color, seems like his fins are also receding.
How has your betta fish's behavior changed? He began to dart all over his tank for a few seconds, and then sinks to the bottom of the tank and seems to gasp for breath.
When did you start noticing the symptoms? Today.
Have you started treating your fish? If so, how? No, no clue of what this even could be, let alone how to treat it.
Does your fish have any history of being ill? Yes, he just got over ammonia poisoning from the pet store cups.
How old is your fish (approximately)? I'd put him at 6-8 months at least.