Help my Betta fish is not acting right

[Fishykidgarry]

My Betta fish that I got from PetSmart a year ago is starting to act kinda funny, he stays at the bottom of the tank, not moving, and is oriented at an angle. When I put my finger near the glass of the tank (where he can see it) he darts around the tank and goes up to the top of the tank (for air I'm assuming) and returns to the bottom on his side. He doesn't eat food that much anymore, maybe 1-2 pellets and I'm really worried for him.
INFO:
Breed: Twintail Halfmoon Betta (male)
Tank: 5L Top Fin (nutrafin Betta+ tap water purifier)
Food: omegaone Betta buffet pellets (he doesn't eat API tropical flakes or nutrafin basix blood worms, he never ate these even when he was okay)
Heater: set at 90F (but water feels kinda cold, thermometer reads 82F)
Has a mystery snail as a friend
I use a small Betta fish filter that uses EF-S cartridges
No vegetation or rocks in tank

 

[Fishykidgarry]

Also I thought he had a bacterial or fungal infection so I used a topfin bacterial and fungal herbal remedy according to the instructions and it didn't do anything

 

[Deleted member 149562]

The heat is too high to start with. It feels cold to you as a human cos your body temperature is way higher than that of a tropical aquarium, 78 max is all that he needs.

5 litre aquarium is way too small....5 gallon is the absolute minimum he needs

He also needs substrate, plants (real or artificial) to feel safe and secure and floating plants of some sort. Once he has plants and feels secure and safe and his temperature is brought down, he will likely perk up again. Lighting on for no more than 8 hours per day, he needs darkness to rest.

In his current conditions the fish is highly stressed out.

 

[Fishykidgarry]

Okay I turned down the temp to 78-80F and I made a mistake it is 5gallons I accidentally wrote liters, but I never had fake plants in my tank before so why is it now that he is acting irregular besides the temp?

 

[Deleted member 149562]

Okay I turned down the temp to 78-80F and I made a mistake it is 5gallons I accidentally wrote liters, but I never had fake plants in my tank before so why is it now that he is acting irregular besides the temp?

Without appropriate cover and places to hide his stress levels will rocket, as he gets older his ability to handle that level of stress will diminish. All fish need places to hide and feel comfortable, safe and secure. Two resin structures are simply not sufficient for any fish, substrate is also comforting and helps balance the water chemistry.

Please do not use any medications without a definitive cause of his behaviour.

What is the water chemistry (in numbers)?
What is your maintenance routine?

That poor fish is living in what is effectively and overheated box of mirrors and it is stressing him right out.

 

[Fishykidgarry]

Okay so get some plants for the fish and the maintenance routine is 50% of the water replaced every 2 weeks (with purifier) and a new filter every month. I don't have the chemistry set for the tank but I'm planning on going to PetSmart to have them check over the water

 

[Deleted member 149562]

You should not be changing the filter monthly...or the media within it.

The manufactures tell you to cos they are getting money from you.

Media should be rinsed in the old aquarium water each water change (ideally weekly water changes on such a small volume aquarium). Media should only be replaced when it is literally falling apart in your hand when being rinsed and part of the old media should go back into the filter with the new media since the media is what is growing and maintaining the good bacteria needed to help keep the water healthy.

By changing the media so often you are pretty much doing a constant cycle, that along with the lack of substrate that also holds good bacteria and the lack of artificial plants (that can hold onto good bacteria) and real plants/cover plants that help oxygenate and keep water healthy.

From what you are saying and the basic state of the aquarium, I suspect the water quality is off....potentially fatally...due to the poor maintenance regime, constant media changes and nothing whatsoever to hold or grow sufficient good bacteria....along with the highly stressful box of mirrors that the fish is living in with no escape or security from his perceived predators...such as his own reflection.