EDIT: Sorry, i've updated the post with the outline.
What size is your tank? 2.5gal
What temperature is your tank? 78f
Does your tank have a filter? yes
Does your tank have an air stone or other type of aeration? yes
Is your tank heated? yes
What tank mates does your betta fish live with? none
What type of food do you feed your betta fish? Topfin color enhancing betta bits // topfin freeze-dried bloodworms
How often do you feed your betta fish? 3 pellets twice a day
How often do you perform a water change? weekly
What percentage of the water do you change when you perform a water change? 50%
What type of additives do you add to the water when you perform a water change? topfin betta water conditioner
Have you tested your water? If so, what are the following parameters?
Don't have an indepth testing kit yet, but his Ammonia level is fine according to the meter on the tank.
Symptoms and Treatment
How has your betta fish's appearance changed? White 'slime' on underside
How has your betta fish's behavior changed? Stopped eating
When did you start noticing the symptoms? This morning
Have you started treating your fish? If so, how? Went out and bought Rid Fungus but haven't used it yet
Does your fish have any history of being ill? don't know
How old is your fish (approximately)? don't know
I'm a brand new betta owner and i just got Boris two days ago, so any help you can provide is greatly appreciated.