Help: Dottyback turns agressive and hosts Toadstool (videos)

[mechslave]

http://www.youtube.com/watch?v=csNzYMj4SGE
http://www.youtube.com/watch?v=ZRmQvdAbcus
Ok, this is weird. The toadstool has been in the tank like a month, and the dotty has never been agressive at all and never showed any interest in it. All of the sudden I get home today and he is in the toadstool and defending it very aggressively and has the tangs stressed out. He lays in it with his dorsal up, like a snake in the grass!
He's never been aggressive before. Has he/she just matured and this is a nesting instinct and will pass? Or will I have to remove him? Notice the dark color of the Sailfin, the color he changes to when he's annoyed. The dotty really does not like the Purple Tang either as of today, even though they've been fine for at least 2 months!
Any ideas?
Sorry for the poor vid quality.... just did it real quick with my digicam.

 

[promisetbg]

He's a neon dottyback...they are definately aggressive. Does he have a cave to call home? All dottybacks need a hiding spot to feel secure.

 

[batman1820]

Uh oh... aggressive dottyback. You should try giving it different kinds of hiding spots until it finds one it likes. Otherwise you should return it. I had an australian dottyback that was about 4 inches long in my 385 gallon tank with hiding places everywhere, but it was still so aggressive that it killed a 7 inch greenbird wrasse and started attacking all it's tankmates that were even larger than it. There was no way for me to pull it out of the tank and it was a real pain in the butt until one day my lionfish got big enough and ate it

But neon dottybacks aren't usually as bad as australian dottybacks so hopefully you will have better luck than me. How big is your tank?

 

[mechslave]

I found it odd that he's been in there for 5 months and never so much as nipped at any other fish and yesterday, completely out of the blue, starts hosting a toadstool and striking at any fish that came by... as though he turned insane overnight.
My tank is a 110.

 

[batman1820]

That is very weird especially in a tank that size. I would just return it.

 

[swlover]

Maybe needs a girlfriend?? You could get him a mate. I know some animals get very aggressive during maturing, and biologically need to mate. Worth a try if you want to keep him.