Paring Mandarin & Aggression

[astrofish]

Hey guys, I've been having a hard time pairing mandarins and wondering if anyone has experienced something similar.

I have both spotted and blue mandarins, male and female, and I've noticed the same pattern several times. When I first introduce them, they're usually fine for the first few days and sometimes even look like they're pairing up. Then after a few days or a week, one suddenly starts chasing the other pretty aggressively.

With my blue mandarins, I had a male that stayed together with a female for about a week, then suddenly started chasing and nipping her fins. She eventually died, most likely from stress. He then started doing the same thing to another female, so I separated them.

I've seen similar behavior with spotted mandarins too. It's not always the male either. I've had a larger female attack a smaller male before.

Right now I have a larger male spotted mandarin with a slightly smaller female. The female was already established in the tank. First day they were fine and I even saw what looked like some courting behavior, but the next day the female started chasing the male whenever she saw him.

The weird thing is, if I put both of them together in a small isolation box, the aggression completely stops. There's no divider between them, but they don't fight at all. Put them back in the display and eventually the chasing starts again.

I've seen this happen more than once now, so I'm really curious what's going on. Has anyone experienced this with mandarins? How did you successfully get yours to pair?

 

[exnisstech]

I've only paired them once. I had an established female and added a smaller male. She tossed him around a few times then they figured it out. I never saw aggression from the male, maybe because the female was considerably my larger?

 

[DaJMasta]

I've paired them a few times and never really run into issues - there is some initial aggression that can be largely defeated by a clear plastic introduction box and then the subsequent chasing, to my understanding, is normal courtship/territoriality behavior, I've seen several males do the same (though my current one didn't, he and his mate were both a little smaller than the average wild caught fish and approximately the same sized, introduced at the same time.)

What's the tank like? Do you have enough coral/rockwork to easily break line of sight in a chase? How often are you feeding and what?

In my experience some amount of nipping is reasonably common, but it surprised me a couple times how intense the chase was - to the point that separating them after that could be useful (I never had, though.)