Yeah, another problem can be if your gar has the usual top-dwelling behavior and the food sinks too fast for them to notice it. I would come up with some way of keep the food on the surface, maybe with one of the vegetable clips... but if you do hand feed them, stop once it's able to get the food, as 1. gars can damage their snouts if they chomp down on something hard when small (such as a human hand, thanks to Polypterus for this info), and 2. getting bit even by a smaller gar can really hurt, believe me!