With dats, never ever ever ever get 2. It doesn't seem likely that you will, but that's what to avoid. And frankly, I think 3 is too little unless they're very fat, lazy adults, who happen to be particularly non-territorial.
They will definitely establish dominance quickly, and in my experience they grow according to that. Usually the most dominant ones will eat the most and grow the fastest, and are *usually* the stable ones (in terms of markings) in my experience. And there's going to be a couple of ashy gray ones hanging out in holes in driftwood, growing slow.
As for pellet training, I found it helpful to raise them on a sort of baby mash of frozen small food (usually mysis) supplemented with liquid vitamins and freeze-dried krill. I'd mix strong-tasting pellets (nls garlic) into that and let it all dissolve into a mushy brown goop. Sometimes there'd still be solid bits of pellet in there, and the dats learn to consume it along with the rest. You can slowly shift the proportions till it's mostly just pellet as they grow and if you're slick they won't notice the difference. And the whole time they'll have been eating a varied, nutritious diet and growing quickly.
