My Black Ghost Knife eats frozen blood worms and frozen brine shrimp... I have never seen him eat fish flakes.. I know that they will eat what is stuck between the gravel... Mine is ALWAYS checking the bottom of the tank for floating bloodworms.
He get's along with my Bala, Silver Dollars, Gourami's and Pleco.. I have 3 hiding places he uses. If another fish is there he will kindly shove him out of the way... quite funny
From what I have also read... they are night owls and are not fond of light... I know mine is out in the day or will hid in his favorite spots...
I honestly don't know how well they can see.. Mine will not eat out of my hand yet but heard they do that.
I don't know if they eat pellets or not. I also am not sure how fast they grow