My Betta was in the care of a friend for the last 3 months so his recent history is unknown to me, other than he has always lived in a 2.5 gallon tank with 76-80 degree water (I use a heater that automatically kicks on if the water temp falls below 76 degrees), and a filter. My friend used all the same thing except for the filter while he was in her care.
He is 2 years old and normally a very active fish and very alert and curious.
When we got him back I noticed he didn't seem like himself. Then after about 2 days I noticed his side puffed up and he started floating to the top of the bowl. No pineconing so I ruled out dropsy and thought it might be swim bladder. I fasted him for 5 days and no change. I gave him a couple cooked mashed up peas but he did not eat them and after reading some things, I'm glad he didn't because I read it can make matters worse in their digestive tracts. He has lost weight and now there is only one side that has a lump on it. He also has slightly protruding eyes (popeye?), and a new brownish color on his chin. With this many changes my first thought was infection.
He is now on the 3rd day of a Maracyn Two. I hate using antibiotics but I got very nervous after researching all of his symptoms that this was an internal bacteria infection? I'm not sure what else to do for him. I am really scared I am not doing the right things to help? I gave him 3 presoaked pellets today because every time I went near his food he seemed like he couldn't go another day without eating!
Any thoughts or ideas?