I have kept them, and the 2 other Tomocichla species, asfarci and tuba.
Picked up half dozen 1" seiboldi juvies at the gcca classic couple years back.

The dominant one slowly killed off all others over time in a 75 gal tank.
It was about 7" when I took it to the last MAS auction, after it had killed the others.

I have found both tuba and seiboldi to be quite aggressive with each other, all 3 seem to need heavy current, and high oxygen levels to remain healthy.
Although tuba have been the most lethal, searching and killing each other off as 2" juvies in a 150 gal tank, I managed to raise 3 males to adulthood. I gave the 3 to a friend who had a large female, she killed 2 of the males and bred a few times with the remaining male before killing him.

Her wrigglers are the dark wavy line below.

The asfraci (hardest to get) have been most tolerant of each other. I received 10 at the Indiannapolis ACA convention, but most had defective mouths, and died during a pump failure. I gave the last non mutant away to an MAS member witha few othe asfraci, and heard it and the others recently, mysteriously died.

The rheophillic Tomocichla are some of my favorites, but I have not found the secret to keep them from killing each other, as of yet.
Although aggressive with each other, they were not overly aggressive with non cichlids.