Hi all. I am very worried about my two male betta fishes. They are all sick. The white one has swim baldder disorder I think. He cannot keep his balance and always floats up when he wants to swim to the bottom. The black one has rotting fin. His original appearance is in picture 3. They are in separate tanks. Each tank is 3 gallons and they are the only live life in the tank. I fasted my white fish for about two day and began to feed him the frozen peas. Today it is the third day of feeding peas. I found he poop two time after I fed him peas. But his stomach (or the swim baldder?) is still bloated. I didn't see him get better. He is even worse now. He likes to hide in the area between the tank and the heater to keep balance(as picture 1 showed). And he is not active now. Could any one please tell me what should I do next? Should I continue feed him the peas or should I fast him again? I put a little aquarium salt in his tank but I don't know whether that could help. For the black one. I changed the entire water on Sunday, added the aquarium salt to his tank. Yesterday I added ERYTHROMYCIN. He is still very active and likes to eat. But I am wondering how can I know whether his fin stopping rot or not, and what is the sign to get better. I was very depressed and busy in the past month. So I didn't take too much care of them. I changed the water in about every 2 weeks and fed them every day and that's it. I am vey new to fishes so I didn't find the symptoms early. Actually I think they began to sick at least from April 2nd. But at that time I didn't notice that. I feel very regret and sad. Please help me if you have any idea. I really love them. Thank you very much.