Clamped Fins and Lethargic

[TielBird101]

Housing
What size is your tank? 3 gal
What temperature is your tank? 78
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? A black Mystery snail

Food
What type of food do you feed your betta fish? Aqueon Betta Pellets
How often do you feed your betta fish? 5 pellets a day

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? 100% on Saturdays and 50% on Wednesdays
What type of additives do you add to the water when you perform a water change? Nothing except the water conditioner (of course. ^.^) and Tetra plant fertilizer.

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? No.
How has your betta fish's behavior changed? His fins are clamped and he's VERY lethargic but he still eats like a little pig.
When did you start noticing the symptoms? The day before yesterday he started clamping his fins on and off and acting a teeny bit lethargic.
Have you started treating your fish? If so, how? No, just an extra 50% water change this morning.
Does your fish have any history of being ill? Nothing besides minor fin rot when I got him in October.
How old is your fish (approximately)? He's approx. 8 months old. :)

The day before yesterday Peach started acting a bit lethargic and clamped his fins now and then. He's still eating fine but today his been sitting on the bottom of his tank and still has his fins clamped. I've had for about 3 months and he's always been real chipper and eyeing the snail now and then. I always add water conditioner after every water change and acclimate him for about 30 min. Please help me! IDK what to do. :(

[chrissylee13]

huh, well this is interesting. honestly i personally couldn't tell you the problem. did you recently start using the plant fertilizer? only time i've witnessed clamped fins is when the bettas have been too cold.

[NflLover101]

I'm sorry bout peachy, maybe it's just a bug or something. As u know my thoughts and prayers are with him and u at this time. :)
*hugs*

[callistra]

Are you using aged water? Sometimes water ph is unstable from tap and if you don't age it can cause big ph swings during larger water change that will really stress a fish. Trust me I learned this the hard way. My ph is so unstable I have to age in gallon jugs for 2-3 days to stabilize fully. If you're not using aged water that would be my first suggestion, or at least get a ph test kit and check it out.

Also how do you acclimate? Is the temp of the water fluctuating when you do a change? This can also cause problems you are describing.

Also suggest fasting one day a week. Is he pooping daily and does it look normal?