Argentine Horned Frog ( Ceratophrys Ornata ) I kept them for over 10 yrs and even bred them. They are fun to keep and will eat anything they can fit in their mouths. Since most AHF's spend most of the time in their water dish, I kept all of mine in 5 gallon tanks with a small incandescent light for warmth. with nothing but about a 1/2 - 1" of water depending on the size of the frog. I would remove them for feeding.
If you get them as a baby ( quarter sized or smaller ) they should be feed every day a few crickets or mealworms that have been gut loaded and sprinkled with vitamins and calcium supplements. I fed them in a small shoe box. If you feed them in their tank remove the extras when they are done eating/ Crickets left in the tank can actually bite the frog and harm their eyes.. As they get larger you can feed them pinky mice and then move onto to pinky rats a couple times a week. Adult frogs can probably be fed less frequently - the best guide is to feed based on your frog's body condition (if your frog is getting too round and fat, cut back how often it is fed).\
Pacman frogs are not terribly difficult to care for, so can make a good pet that is quite attractive and interesting. However, people who like their pets active or interactive may get tired of caring for a pacman frog. Considering a these frogs can live for 7 -10 years, getting one of these frogs amounts to a long term commitment.
You can keep night crawlers in the fridge. Toss one in and after he eats it give him a minute and feed him another. If he doesnt eat it remove it and save for later.