Sudden Aggression HELP

[Cobrasvt1999]

So im trying to make sense of this and some help would be appreciated! for the last 2 months, my two clownfish have been doing very well together. they where bought both small and together. Suddenly today however the "slightly" larger of the pair found the annenome and became very aggressive towards the other clown. actively chasing him into the corner, where he is now laying and breathing hard.

Anything I can do to help this?? I dont have a standby tank unfortunately

 

[QuickxSilver]

You can try a drop-in isolation box, I'm currently going through that and it looks like I'm going to have to sell one of them. I'll let her out of the box after a few days but she goes right back after the other one.

 

[Uncle99]

This is not good, the loser with get quite stressed and either die, or worse, but subject to disease.

I like the above idea of isolation for 48 hours, then try to reintroduce, you can try this a few times but if it's the same answer each time, the loser should be removed.

I am thinking the slightly larger has turned/is turning female and sometimes this behavior just stops, sometimes not.

 

[ThRoewer]

As a first measure, I would isolate the aggressor in an acclimatization or breeder box so that the weaker one can recover in a familiar environment. After the weaker one has fully recovered (I would give it at least a week) I would try to reintroduce the aggressor and see if they now get along. If the fighting starts again you may have to remove one of them permanently.

How long have they been together and how large are they?
How did they act with each other before, like a pair and always hanging out together or like two individuals that got along but went their own ways?
When was the anemone introduced?
Did you change anything else?