Sick fish but cant figure out problem

Question
Hi Jaymie. I have what seems to be a sick betta fish, but I can't figure out what's wrong with him. He has had labored breathing for about 2 weeks that has gradually gotten worse, and now he keeps sinking to the bottom of the tank and it takes him a lot of effort to swim to the top and stay afloat. When he's hovering near the surface, his backside sinks downward as if his tail is weighing him down. Other than that, his behavior is normal, he has a healthy appetite, no color fading, no flashing or rubbing against anything in the tank, and nothing externally wrong with him that I can see. I've checked him over and over for external parasites or sores. He is a light color, so I've used a flashlight to check him over, but I see nothing unusual on him. There are no discolored spots or blisters or anything hanging off of him. His body, fins, and gills all appear to be normal.  

Just a little history, I've had my betta for 2.5 years, I got him at the pet store so that would probably make him about 3 to 3.5 years old. He is in a 5 gallon tank, heated but not filtered, and I do regular water changes to keep it clean. The temperature in the tank stays between 78 to 80 degrees. I feed him twice a day, 3 pellets a day. Two days during the week I'll feed him one pellet and 3 freeze dried bloodworms. The only health problem he has had before was mild fin rot that is gone now. The fins are growing back, but slowly.

I don't know why he's breathing so heavy, and why he has so much trouble swimming. I've done tons of my own research, and all I could find with his symptoms is swim bladder disorder and old age. I don't think it's old age since I know these fish can live over 5 years, and I don't know about swim bladder because it says nothing about labored breathing as a symptom, although he does have most of the other symptoms. I'm fasting him right now and I will be giving him a thawed pea later on just in case that is the problem. I did see some feces at the bottom of the tank which I cleaned yesterday, and it did look normal, at least the color was normal. I've kept the tank bottom bare so I can monitor his bowel movements, and so far I haven't seen any since yesterday afternoon. I have tons of medications at home that treats parasites and bacteria infections, but because I don't know for sure what he has, I haven't given anything to him. I was thinking if he has an internal bacteria infection, I wouldn't be able to tell. If he's not going to get any better after feeding him the peas, should I put a jungle fungus clear tablet in his tank since it treats bacteria infections? Or should I not give him anything until I know for sure what he has? This is really frustrating, and I feel so helpless not knowing what I can do for him. I just hate seeing him like this. :( Please help.

Answer
Michelle,
Usually labored breathing means there is little oxygen in the water. This usually is taken care of by adding an air stone to his tank. As for treating him with medication, it is not advisable to treat unless you know what's wrong. The Betta's stomach is the size of his eye and over feeding can happen. I would feed him once a day and depending on the pellets, no more that 2. I have tried many Betta pellets and have found that most of them can cause constipation, which can be mistaken for swim bladder disease. When you feed the pea, it is best to fast him for 2 days first. On the third day, feed him a cooked shelled pea and then fast again for 2 days. To help prevent constipation, fast him once a week and feed the shelled cooked pea once a week as well. I would also replace the freeze dried bloodworms for frozen bloodworms. Freeze dried foods for fish are like fried foods for us. Frozen bloodworms are better and he will like them much better. Let me know how he is doing after you feed him the pea.