Like the others, there is no way a "healthy" tang is going to be caught by a shrimp. And especially a yellow.. It would rip a shrimp to pieces! The tang was probably on its last breath, or should I say, last fin flip.
Sorry about the loss of the tang though.. I won't say b.s., as, lol, it's harsh.. But they're right.. The poor fish was basically gone when the person saw the shrimp grab it. And the shrimp, like crabs are either opportunistic or symbiotic. It basically saw a free meal for its friend(the Condi) and gave it to it.. But the tang was already gone..
It's the way of nature unfortunately.. Sorry for the loss once again..