Ya me too. I got a big black after my afro died and I'm just not feeling it at all in comparison. Afro always constantly moving, sifting sand, being a dick to the other fish. Not freakingout all skiddish with movement like this black. I miss it.
Black's can be skittish but it all depends what you have for top swimmers. Would you rather have a fish that causes chaos or one that is more mellow. My black's are perfect tank mates for stingrays as they don't bother the rays and the rays don't bother them. They don't beat on fish and never had one with drop eye. It also depends on the size of the tank too...if you put it in a small tank it will be skittish. Put in a 450 gallon plus and they are mellow and cruise all the time. I tried other top swimmers and it never ends well for the arowana as they always stress out if they start getting chased by another fish. Just happened to my 30" male as he started getting chased by a big red tail gourami. I moved the gourami but stress had already set in and the aro hasn't ate for a month. Hopefully he comes around as I have had him for about 6yrs.
If you have a rough predator tank and fish have to fight off each other then I guess you would have to go with one of the more aggressive arowanas.
Hence it is trial an error until you have harmony in your tank so you don't have to babysit and medicate beat down fish all the time.