Looks like a goner but kudos for the save and good luck.
Its not vittatus, its probably a brevis (can't really tell when they're that emaciated). Brevis is also the hardest to get off of live, hence the state of that fish. It's likely been starved since the large batch of Nigerian tigers came in last summer.
I had a brevis that was about as bad as that one and it never got better and eventually died after a water change.
Ummm, why would you not want to do water changes? I would think the cleaner the water the better.
Wow, he is really skinny. Good luck fattening him up, I'll be really happy to see him make it through OK.