Betta fungus?

Question
QUESTION: Hi, I have one male betta fish in a 2.5g tank with a whisper filter. PH is 6.6, nitrite/nitrate within safe range and temp at 80 degrees. My tank just finished cycling (I think). After about 5 weeks my filter was gunky and not working so I changed the cartridge/carbon (did not clean the filter). The water itself is clear but the top of the water looks thick- like oil in water. I have done partial water changes, treated the water, and add aquarium salt. I test the water about every other day to make sure it's ok. My fish has a healthy appetite, swims, flares, and makes bubble nests. A few days ago I noticed a patch on his body, near his head. Because he is royal blue and the top of his head/body are dark, I couldn't tell what the patch was. All I know is that it caught my attention. In the meantime, I have been researching fish diseases without much luck. It doesn't look particularly fluffy. And it's more gray- even darker. I thought I would wait and watch to see what happens. Today I noticed there are 2 tiny white spots on it now- they look raised. Parasites? There are no other patches/spots elsewhere. I thought it might be fungus but because I am unsure, I don't want to treat him with the wrong stuff. I can't imagine what caused this- for some reason the pH was very low for a few days (but within safe range) and after I changed the cartridge, the nitrites shot up but I got it down within a day or so. I have used aquarium salt regularly. Please help! Thank you!

ANSWER: I don't know what you are using aquarium salt for because betta's are freshwater fish. Those white spots you are seeing are called ich i would use rid-ich to cure it. I have never heard of fungus being that color it is white i thought. I would wait and see if the growth gets bigger if it does i would use "Jungles Fungus cure" to cure it.

---------- FOLLOW-UP ----------

QUESTION: Thank you for your rapid response. I have used aquarium salt based upon the advice from almost every betta fish website I have seen. It is used to aid in reducing stress and enhancing fish disease treatment in tropical fish. My question- does ich spread rapidly? So far it is isolated to one spot. The pictures of ich I have seen are completely covering the fish. Thank you!

Answer
Well your fish shouldn't be in stress anymore he has been in that tank a while. I wouldn't use salt in the main tank i would get a separate bowl and put salt in separate tank.
What i do is give the fish salt baths for about 10 minutes everyday then put the betta in the main tank with rid-ich and that is how i treat ich with my bettas.

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