8 inch is small but still a fairly decent size, should be able to last a few weeks without food. Don’t worry it is just acclimatising to the tank. I’ve had gars go for weeks without food. Previously had a 13” florida gar go 1.5 months without food. If worst case scenario I would throw in a few feeders.
don’t feed bloodworms, too small for your gar and the leftovers would just float away and rot in your tank resulting in buildup of ammonia and nitrate. Even if it catches some of the bloodworm cube some of the bloodworms would just fall from its mouth. Provides little to no nutritional value as well. I would go for frozen seafoods such as tilapia or market prawns.
Best way to feed a gar in any circumstance is to literally drop it in front of its snout/ face when it is at the surface. Its reflex would be to just grab the food when the water splashes, I could drop a rock in front of it and it would still grab it. Gars like still to slow moving water, if you have high flow it can be another reason why it is stressed out. I would feed it in an area that the water movement is low.