Marie,
Did your clown kill the other ones or did they just never pair up? I'm just asking because I have a big female and was trying to pair her with a ~2" one. She chases the smaller one, but doesn't hurt it. They don't really swim near one another, cause the smaller one is afraid of the bigger one. They've been together for a little over 2 weeks now, and I thought they'd act more like a pair by now. Should I go and buy a tiny one to replace the small one I have now or is it too soon to tell?