I've never seen a Mandarinfish act so aggressively...

[dzones]

You see I can relate cause I feel the same way about clowns...they kinda freak me out.

 

[loumaggs]

Does your male have a female friend? I wonder if there is eggs back there and he was protecting the nest?

No female... might be part of the problem

 

[Oscaror]

Well mandarins aren't that smart, they're fish, maybe it mistook the clownfish for another mandarin because of it's similarly shaped fins?

 

[AlexG]

I had a spotted mandarin that was like this in my last tank. I was trying to make a pair. Unfortunately it never worked out. I had to return several fish I thought were female. There was one pairing I thought was successful but it later failed when the mandarin murdered its partner. I had a pair of spotted mandarins years ago and they were always together I really enjoyed these fish. I will be trying to get a pair together in a store before I but them this time around. I just need to finish building my setup.