Í got my finicky gars onto floating aro sticks, and eventually sinking sticks, the following way...
For the 1st couple of weeks, the gars are fed live minnows ALWAYS FROM THE SAME CORNER OF THE TANK and one-at-a-time.
After a couple of weeks, I'd offer a minnow then a floating aro stick or FD krill or thawed raw shrimp. They'd snap at the sticks/shrimp while expecting a live minnow. By the end of the 3rd week, all of my gars were readily taking sticks.
Now, my trops, shortnose, longnose, and gator gars all take floating/sinking sticks, slow-sink salmon pellets, FD krill, etc. And, they've been off live foods for a year or more. This years newest gars all quickly took to the sticks by watching the others and no minnow weaning was required.