Hydrolycus sp. shoaling question

[Luc]

about the 10" range. after that, have lots of room and lots of dithers.

IME they mellow out at about 20" and do better with tankmates their own size...

Thanks for the info.
There is a good chance, one day I come back from work, one of them can turn belly up cuz of fighting among themselves? I saw in a post somebody's Tat(much more subdue than Armatus) can kill it's own kind.

Anyways to reduce fighting? More tankmates? Wat types of tankmates suitable?