I just went through something somewhat similar, but yesterday I noticed my water level was a bit low, I checked my salinity level and it was 1.026 way too high. Anyway I brought my salinity back down and today he looks much better. My Hatian died due to this and I never thought it was something so simple. Anyway check your water readings, the answer could be right under your nose.
Bubble tips IME (so far) can take a beating for only so long, mine went through a 6 day struggle until I found my mess-up (I got lucky)
Dan