My male betta Zorro has been very lethargic in the past 2 days. He used to swim around the tank but he has been hiding in his cave and is swimming funny too. Every time he stops swimming, the fin part of his body starts to drop and he becomes vertical in the water. He's been trying to fight it off but today I noticed that his scales are starting to spike up.
Please help. I did a 25% water change yesterday. What should I do?


Housing
What size is your tank? - 2.5 Gallon
What temperature is your tank? - 77 degree
Does your tank have a filter? - Yes
Does your tank have an air stone or other type of aeration? - it's open from the top
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? - pellets, dried shrimp, blood worms
How often do you feed your betta fish? - once a day
Maintenance
How often do you perform a water change? - once a week
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? - water conditioner
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? - scales starting to spike out
How has your betta fish's behavior changed? - used to be active, now lethargic and hiding
When did you start noticing the symptoms? - 2 days ago
Have you started treating your fish? If so, how? - Added epsom salt to water
Does your fish have any history of being ill? - no
How old is your fish (approximately)? - 6 months