When I first got my betta, he had beautiful flowing pink fins and was extremely active. It has only been about 4 months since I got him from the pet store. For the first 2 months he was happy and healthy. I studied abroad for 6 weeks, and when I came back and he is very lethargic. His fins have also began to droop, I cannot tell if there is any extensive fin rot because of how they are drooping and because he spends all day hiding behind the filter or inside of his hut. He seems to be floating a bit on his side. He can swim though, and I dont think he has a severe sinking or floating issue (yet) because he doesn't just float at the top or the bottom. He most often rests at the top of the water behind the filter, but sometimes he rests at the bottom in his hut. Last night when I did a water change, he spent a while resting behind a moss ball on the ground. My mom had very specific instructions on how to care for the fish while I was gone. I also have another tank of 5 neon tetras and 1 snail and they are doing perfectly fine. The only issue I noticed when I got back from Europe was that the water level was too low. (My tanks don't have hoods so in the summer they have to be topped off frequently to make up for evaporation.) The water parameters (I don't remember exactly so please don't ask) weren't perfect but they were ok. I suspect that he was probably overfed while I was gone, so I have been fasting him for about three days now. I tried feeding him a garlic soaked pea but he won't eat it. I tested the nitrite/nitrate levels with the API test kit. Nitrite was 0. Nitrate was a little above 0 but nothing dangerous. The betta tank is a 5 gallon with a heater and a filter. It is planted with 3 plants and also has 3 moss balls. He also has a little hut as I mentioned. I did a 30% water change when I returned and a 10% last night. I added some stress coat during the large water change. I can't figure out what made him sick or what I should do to attempt to heal him. I get nervous about adding bettafix or all cure because I've read conflicting information about whether or not they work. Also, please note that I live in a fairly rural/suburban area. There aren't specialty fish stores around to get live or frozen food from. Nor us there anywhere to get antibiotics or medication that Petco doesn't sell. I'm looking for realistic advice here, even if that means "maybe he's just old/sick and going to die". Yes, the tank was cycled before I bought the fish. I set up the tank in March before I went back to college and had my mother tend to it. I continued to cycle it 2 weeks after I got back before adding the fish.