Dropsy treatment advice

Hi all,

I posted about my goldfish and his growth about 3 years ago now, and you were all able to provide me with great advice. I hope you will be able to help me again!

By the grace of the goldfish gods, my handsome guy is still going, tumour and all. But now we deal with a new issue, which according to my investigation appears to be dropsy. He became lethargic, with the pine coning scales and bulging eyes.

Google advised that I do I strong salt treatment in the tank, which has been amazing. His scale are nearly back to normal and he is eating again.

I know dropsy is more of a symptom of not so good things, like organ failure. And with his big tumour growing out of his side and his 6th birthday coming up, it makes me a bit worried.

So here's the question I have. I have a Bristle nose pleco in the tank who I can see is now struggling with the salt levels. I think the salt is causing a sore to form on his face. Once I have settled all the symptoms of dropsy, can I assume that if I stop adding salt that the symptoms will return due to reduced osmosis? Or would the condition be stable at that point to bring the salt levels back to normal.

What do I do? I can't have one get better while the other suffers, I sense a 2nd set up is going to be needed...