fishing stuck at 75/75 and is maxed out without any ability to increase, please rectify asap
Fishing for which expansion and where are you trying to fish?
Fishing max skill of 75 sounds either Outland, Northrend, Cataclysm or Pandaria fishing. Max skill for those area is 75 so you need to switch to a different area if you want to level different expansion’s fishing skill. Make sure to train the skill required for that area (usually found in that particular expansion’s main cities for example).
If it’s retail then you are at max for that zone, if it’s classic go to a trainer and get it to 150. More than 150 needs a book.