Hi Lion King!Not the freckled specifically, try live ghost shrimp or appropriate sized mollies. Like any angler it's best to feed them a few smaller items than a really large one, and you will need to provide live prey. Ghosties and mollies are the best food, but in a pinch guppies aren't bad. the problem with guppies are they can float, while mollies will acclimate and hang out until he eats them. It's really important to get him eating, so don't waste time, they can go to a point of no return. If you can't get ghosties or mollies, these are things I've fed in a pinch; peppermint shrimp but an expensive meal, a fancy guppy appropriately sized, a platy. I really don't like to, rosies would be your last resort. I shy away from salt water fish mainly because of risk of disease, and the price of course.
I also just purchased a Freckled Angler from DD. Is it better to feed freshwater or saltwater ghost shrimp? Also, do you think he will try to eat my Yellowspotted Scorpionfish? My Scorpionfish usually stays hidden in the rocks so I'm hoping it won't be an issue.