Would nitrate go too high if pwc done every other weeks, only max of 30% at each pwc?
Or adding driftwood to tank? We just dont know if suffering from exposure to higher pH!
As far as med, I used to use Folmaldhyde/Malachite Green combo med (Formalite I; wonder drug; by Aquatronics but no longer avail) but Aquarium Products Quick Cure has same ingredient, I believe.
Make sure fish is free of any open wound, DO NOT USE ANY MED WITH FORLMALDEHYDE and/or Malachite Green on OPEN WOUND..
But before using that med, how about RED BLOTCHES/SPOTS? I think it should be addressed first before clamped fin since internal bleeding, if it is, can be more fatal than clamped fins.
On internal bleeding, used to use Kanamyacin (Kanacyn by Aquatronics but no longer avail) I do not know what to recommend unless you can obtain Kanamyacin by other possible mfr.
In case, clamped fin develops with whitish clumps on their fin/tail, can add Amphicillin (Amphillex by Aquatronics but no longer avail) but may be other Co mfr.
Its shame that Aquatronics pulled their products off the market. I believe it is due to fact that most
LFS did not know how to diagnose and advice proper/specific treatments since Aquatronics is more specific rather than combo of med and Aquatronics were more costly. Nevertheless, I found most Aquatronics med were better choice by far than other brands.
Always kept just about most meds made by Aquatronics for emergencies, even had confidence on expired Med over other brands.
If can not find Kanamyacin or Amphicillin, how about either Maracyn or Maracyn II but NOT both at the same time.
I used to mix Formalite I with Amphicillin when needed (severe case of clamped fin with bacterial infection of fins/tail) w/o any adverse results but never have done it with Maracyn/Maracyn II so I do not know if any interaction b/n them will take place. Thus would recommend Antibiotics first (Maracyn or Maracyn II but not both) if you suspect internal bleeding. When fish recovers but still have clamped fin/tail, then treat with Quick Cure. Of course, few small pwc/change carbon or add new carbon and remove before adding Quick Cure.
Hope this helped a bit.