The main issue that I was alluding to is keeping the gar & jardini together; said combination will not last for very long due to the jardini's aggression. The impending aggression issues are why I recommended that you return the gar; as long as you were to get an aquarium that is large enough for the jardini, e.g. at least a 240 gallon, then the aquarium would be large enough for the gar, too. The gar is a Florida gar by the way, and it will not exceed 24" in captivity with 18" being the average adult size.
As for converting to food sticks, try to get them on freeze-dried krill as it floats at the surface & is typically very appealing to predatory fishes; once they're eating that regularly then start adding pellets in with each feeding until they'll eat just pellets. I've used that method for converting gars to pellets, so it should work pretty well for you although they don't always take to the conversion as quick as you might prefer.
As for converting to food sticks, try to get them on freeze-dried krill as it floats at the surface & is typically very appealing to predatory fishes; once they're eating that regularly then start adding pellets in with each feeding until they'll eat just pellets. I've used that method for converting gars to pellets, so it should work pretty well for you although they don't always take to the conversion as quick as you might prefer.
