I just got Oberon a few weeks ago. When I got him he had been kept in really gross water at the pet store and had popeye and one swollen gill and later developed a very mild case of fin rot, and I treated him successfully with Maracyn and a rooibos tea/Epsom salt bath. He's been swimming and eating normally and building bubble nests, but I just noticed about a half hour ago that his gills were open but he wasn't flaring. Right now they are both open, but one of them is protruding a LOT and he appears to be breathing heavily out of just that gill. He's still acting otherwise normal. Here's a picture.
What size is your tank? 1.5 gal
What temperature is your tank? 79
Does your tank have a filter? yes
Does your tank have an air stone or other type of aeration? no
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? Aqueon color enhancing betta food and live daphnia
How often do you feed your betta fish? 2 pellets in the morning and a couple daphnia or another 2 pellets in the evening
How often do you perform a water change? every other day
What percentage of the water do you change when you perform a water change? 30-50%
What type of additives do you add to the water when you perform a water change? Aqueon Betta Bowl Plus
Have you tested your water? If so, what are the following parameters?
Not tested lately
Symptoms and Treatment
How has your betta fish's appearance changed? Gill swelling only
How has your betta fish's behavior changed? occasional heavy breathing, but otherwise no change
When did you start noticing the symptoms? Today
Have you started treating your fish? If so, how? Not yet
Does your fish have any history of being ill? Yes, slightly swollen gill and popeye, very mild fin rot
How old is your fish (approximately)? 6 months maybe?
I think some of it might be stress, since I just got back from vacation and I had taken him with me (I didn't trust anyone else to properly care for my little fishy!) Could it be that he's upset from the car ride and that triggered it?