Nice growout group. The primary thing to focus on is to get them on good constant protein feed. You are on a great start to have them on pellets already!
Having said that, do not ever break that bond and feel the itch to introduce feeders just for the fun of watching them hunt.
I would not focus so much on trying to get them to 'stable' at that size. An active 'unstable' Dat is more rewarding than to have a 'stable' hiding in a corner ones.
A trick that you can copy from Asian keepers is to introduce 'aggressive' tankmates like a jaguar cichlid or Texas. However, please note the stress level those Dats MIGHT go through long term for the sake of the keeper's desire to turn them 'stable'.
Of course there are 'stable' Dats that rarely turn 'unstable' and vice versa.
Some claimed that Sumatra and Borneo have distinctive physical appearances. Mixed in a group, it is quite difficult to tell them apart. The only sure thing to know is to trust the Indonesian exporter as to where the fish was caught from.
4 symmetrical bars on each side with Full Neck Full Belt bars running under its body on a Borneo IT can be tricked into passing them off as a Sumatran IT which fetch a much higher price.
