what the heck?! Tomini Tang is not reef safe!

[pcon]

Didn't watch the video, and he wouldn't devour them, he wouldn't relentlessly pick at them till they died... The angel eventually passed of old age, his name was frank and he almost made it 10 years...

But what kind of angel was it? That could be the angels fault or like @Tamberav said could simply be responding to them being in poor health from other reasons.