What is wrong with him!?! Sick Betta.

[littlemew4]

I'm so confused! My betta recently started looking really sickly but I can't figure out what it is. The only thing I can guess is some sort of bacterial or fungal problem but I'm still so confused. The photo attached are from yesterday morning and the white patches he had there are now gone. The last photo is with me shining a flashlight on him if you couldn't tell. When I woke up this morning he seemed way better but by night his colour faded again and when I fed him it looked like he was having trouble getting food that was near the bottom. I'm so confused what is wrong with him he still eat likes a pig. I just can't find anything that would fit this. Am I just clueless? HELP!

 

[Autumnsky]

Please share the size of tank,
Temp,
Parameters if you have them or can get them-
ammonia, nitrite, nitrate, pH GH/kH TDS
Filter?
How long you have been keeping him,
What do you feed?
how often do you change the water and how much?

Is the tank cycled and how was it done?
Did you do a water change the day before the fish was looking better?

 

[littlemew4]

Temp, 80F
Parameters if you have them or can get them-
ammonia 0.25ppm (It's in my tap) nitrite 0ppm nitrate <5ppm
Filter? Just a basic sponge filter
How long you have been keeping him, since October I think
What do you feed? Every day and night with a fast on Friday.
how often do you change the water and how much? once every 1-2 and about %25-%50.

Is the tank cycled and how was it done? i planted BB and used Tetra start
Did you do a water change the day before the fish was looking better? No