I am no expert, I would say starve them until they get hungry. Any fish with time will go for anything. IMO you are better off feeding foods other than live. Live foods can carry diseases. I have a 12inch spotted gar that eats carnivore sticks. I also have a 6" spotted gar in the same tank that I am trying to ween off of live. I just takes time, patience, and training to get your fish to do want you want.