Well I decided to treat with Tetracycline. My clown (Daryl) died

It was really horrible. I went into check on him and he was lying on his side on the bottom. He has always been my favorite. He was my first knife, I had him for 7 years since he was a baby. To add insult to injury, I got poison ivy while burying him in my back yard.
But my royal knife seems to be doing a little better. She is still very kinked, but she has been more responsive. She is also eating better although she still has a hard time catching the goldfish. Now that she is on her own tank, I can just put the goldfish in and she can eat at her leisure.
I did some internet research on fish diseases. And I think it is possible that they have the same Mycobacterium that I have, however I am pretty sure I got it from their tank water after I was stabbed by a piece of live rock in my saltwater tank. Since my infection is under my skin I don't see how I could have transmitted to them. But I am suspicious of the goldfish I am feeding since my fish were in two separate tanks and the goldfish are the common denominator. I am thinking of switching to a sulfadrug antibiotic which is recommended if this is the bacteria, but since my royal is doing better on the tetracycline I will probably stick with it for now. I can always switch later if this one is not working well. I have been on multiple antibiotics on for about 12 weeks so far and my infection is still lingering although it is getting better. I actually do not think my royal will recover given her current state, but I am really hoping she will.
Thanks for all your suggestions. If anyone has more, please let me know. I will keep you updated...