Can clownfish kill coral?

[ScubaSteve]

Clowns can love their host a little too hard sometimes. I had a clown that hosted my duncan for a while and it really beat the crap out of it. It looked closed up for a while but then started to open up again like nothing was wrong.

Duncans can do this thing from time to time where they look really ****ed off and stay closed for weeks on end, then open up like nothing was ever wrong. Duncans are funny like that. And they're stupidly hardy... I doubt your clown could kill it unless it's getting to the point where it is doing actual damage to the flesh of the duncan.

I'd give it some time and see what happens... likely your clown is going to get bored of the duncan an move on.