Some bubble tips just don't stay as "bubbly" as others. I've heard it has to do with where their collected, water quality, if there's a clown aggravating it, etc. I don't really know what the right answer is, BUT, it happens. I have 4 bubble tips, two green, two RBTA, only one RBTA has kept is full tips, the rest all look almost like long tentacle nems now. I blame my fish for destroying mine.