Slanting Betta

[TheSecondOne]

Hello everyone. I'm new to this forum. My betta, First Sergeant Byron, is sick. The details and photo are located below. Any help is greatly appreciated. Thanks.

Housing
What size is your tank? 1.5 gallons.
What temperature is your tank? 27 C, 81 F.
Does your tank have a filter? No.
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? Hikari Betta Bio-Gold pellets.
How often do you feed your betta fish? 6 pellets daily.

Maintenance
How often do you perform a water change? Twice a week.
What percentage of the water do you change when you perform a water change? 95% because my 1.5 gallon tank doesn't cycle.
What type of additives do you add to the water when you perform a water change? API Stress Coat+ water conditioner.

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

Symptoms and Treatment
How has your betta fish's appearance changed? No change.
How has your betta fish's behavior changed? Sometimes darting around and resting at the corners of the tank. Occasional rapid gill movement and lying on its side.
When did you start noticing the symptoms? 2 weeks ago.
Have you started treating your fish? If so, how? Emptied and cleaned the entire tank, performing a 98% water change. Added a little aquarium salt.
Does your fish have any history of being ill? No.
How old is your fish (approximately)? 1 year and 3 months, assuming that I bought him at 1 year old.

[TheSecondOne]

I think I finally found the reason for his weird behaviour. It must be because I removed the aquarium ornaments from his tank during a major water change and that he doesn't feel safe without hiding places. After I put them back in, he's starting to act normal.

[oo3laineoo]

Am having the same issue with mine ! But I didn't removed anything all I did was put a heater in the tank.. Scared he might die. 8(

[TheSecondOne]

What kind of heater is it? Do you have a photo? I've been caring for bettas for 2+ years. I may be able to help.