Peaceful or territorial and aggressive? Emperor tetra (Nematobrycon Palmeri)

[rebe]

I've heard really mixed things online, this is in a community setting. Some say they're dream fish and then I've heard of them being absolute bullies. Does anyone have experience keeping this fish?

 

[Ichthys]

Very peaceful in sufficient numbers (say a minimum of about ten). Males are slightly territorial with each other but do no damage. They’re not aggressive towards other species.
The “aggressive” ones are no doubt kept badly (insufficient numbers, insufficient space, bad tankmates or other stress)

 

[GaryE]

I was always told they were aggressive, and when I had small tanks as a kid, they were. I was going to buy some last week, to see how a dozen in a large tank would be.
They do claim territories and males are a bit touchy, but the territories are fluid. I've written here that they can be aggressive among themselves, but as they have flooded into the local market and I've gotten to see a lot of them, I've revised my view on them. They spar, they bicker but they generally get along. In a 10 or even in the 20s I had them in, they aren't at the their best. In a proper group in a decent sized tank (for them) they seem fine. But numbers seem to matter. Three in a 20 can be trouble.

 

[nodding_dino]

I'd agree with the above - I have a group of 20+ in a 325l (approx 86USG), and see bickering amongst the males - in my experience, expect some war wounds...

The males spend a lot of their time enticing the females into the planted area, so some dense cover is advisable too.