well, i have had quite a few types of loaches, but not kuhlis so all that i owned(clowns, yoyos, zebras, chains, others), they all seem to like any sinking flake(aqueon ones, algae wafers, and freeze dried foods....
Mine go nuts for the Cichlid PeeWee that I give the other fish, this is a sinking food meant for cichlids, but I swear they ought to make it a sinking tablet also! New Life Spectrum is a similar formula, I bet they would like that too.
They will nibble on soft veggies a bit, such as cucumber and blanched zuke, but meaty foods are their preferred fare.