What size is your tank? 1 US Gal
What temperature is your tank? Not sure, but on the cold side
Does your tank have a filter? no
Does your tank have an air stone or other type of aeration? no
Is your tank heated? yes - mini heater
What tank mates does your betta fish live with? none
What type of food do you feed your betta fish? Pellets
How often do you feed your betta fish? usually 2x daily
How often do you perform a water change? usually once per week
What percentage of the water do you change when you perform a water change? 100%
What type of additives do you add to the water when you perform a water change? a generic betta water treatment
Have you tested your water? If so, what are the following parameters?
Symptoms and Treatment
How has your betta fish's appearance changed? He now has a white growth-like spot behind his dorsal fin and one gill cover looks reddish.
How has your betta fish's behavior changed? He seems more listless and doesn't always react when I feed him
When did you start noticing the symptoms? The listlessness about a week ago, but I thought he was just too cold and tried to warm him up. I didn't notice the white patch until tonight when I changed his water, but I was distracted last week so it may have been there for a while.
Have you started treating your fish? If so, how? Just a water change so far, but I have antibiotics from treating my brother's fish that I could use and could pick up some aquarium salt tomorrow.
Does your fish have any history of being ill? None so far
How old is your fish (approximately)? I've had him for a little over two years
Picture attached, though it's not very good. I can take more if needed.