Old Clownfish not getting along with the new guy!

[Coach63]

Hello,
Bought two clownfish about a year and a half ago from the same lot at the fish store. They got along great; sadly, one died about 3 weeks ago so I bought another one to replace the dead one. From the moment I finished QT and put him in the display tank, the old one will not leave him alone. From chasing him throughout the tank to getting right along him and "fluttering" against him. What is going on? I made sure I got one the same or a little bigger in size.
Should I take out the old clownfish for a bit and reintroduce him after the new guy settles in? I do not want to stress the new guy out to the point of killing him.
Please help.

 

[davocean]

Well, usually the safer bet is get a new small clown, especially if you QT'd it, as the old may have been the female, or maybe had time to change to female.

The larger will be female, but in the event the female passes, next in line will become the new female, so you very well could have 2 females right now, and if so that will not work out.

Also, always intro in a floating container and observe the two, see how existing acts towards new clown first.
Sometimes that takes a couple few days, sometimes a female just won't accept some new clowns even if they are a male to female combo.