Please Help Diagnose And Treat Sick Betta. I Don't Know What Wrong

[JungleFish]

My betta wasn't eating yesterday and was floating lethargically at the top corner of the tank. I didn't notice any other symptoms so I did a large water change. Today he is still lethargic, his fins are starting to look ripped or shredded on the ends (like they were damaged or its the beginning of fin rot) and there is a cloudy, white, fuzzy, patch on the fins above where the damaged is (but not on his body) . On one side of his fin there is quite a large blob (for lack of a better word) of the white stuff.
 
After some research I think it might be fin rot and/or a fungal infection or columnaris but I have no idea which. They have some common symptoms but lots of different treatments and I don't want to use the wrong one.
 
 
My male betta lives in a ten gallon heated and filter aquarium with some live plants and it has been set up for about a year. I have an empty 5 gallon for treating, Marcyn 1 and 2 and aquarium salt. 
 
 

 

[sawickib]

Hi welcome to TFF! 
 
Would you be able to tell me what the water parameters are, such as ammonia, nitrites and nitrates?

 

[JungleFish]

Here are two pictures. The circled image show the large white spot.

 

[sawickib]

Looks like a fungal infection, is it cottony? 

 

[JungleFish]

Okay, I just used my test kit
 
Ammonia-- Closest to 0.25 ppm
Nitrite-- 0 ppm
Nitrate-- 0 ppm
 
It seems cottony

 

[sawickib]

You will want to first do a large water change about as much as you can, and then get some meds for anti fungal. I'm not very good with meds but I would just do some research on the proper meds that do best or go to your LFS and read the labels on the meds and see what cures the fungus.

 

[Ninjouzata]

What temperature is the tank at? What is your water change schedule like? (How often/how much)
 
What do you feed him? (How often/how much)

 

[JungleFish]

I feed him betta pellets and freeze dried blood worms. 2 pellets in the morning and 1-2 in the afternoon. I try to do a water change every week but lately its been every two weeks. I take out about 10 liters of water (2.6 gallons).