I LOVE that clicking noise - I always wondered where on earth such a big noise came from because they have such teensy mouths!
Plec it's hard to say what might have upset your clownie . I've never seen mine with their spines out - I think they trigger them as a defensive mechanism so perhaps you are right and the tank vac distressed him? Although I have never heard this happen before. How big/old was he? And how long had he been in the tank? Sorry for your loss anyway.
and now I know!Clicking is from the One row of Pharyngeal throat teeth.
Plec it's hard to say what might have upset your clownie . I've never seen mine with their spines out - I think they trigger them as a defensive mechanism so perhaps you are right and the tank vac distressed him? Although I have never heard this happen before. How big/old was he? And how long had he been in the tank? Sorry for your loss anyway.