I feed my African Butterfly live crickets from the pet store. Once, a larger angle gulped down a smaller one. Later he spit out antenna, legs and other undigestibles.
I was cautioned about feeding the ones around the house. I checked that live cultures site and will take advantage of it when I have room. I also kept feeder guppies but gave the ten gallon to my sons fish. I am down to one fish that eats guppies.
Also, you can breed you own mosquitos, just takes a bucket of water. Just make sure you harvest them before they become a nuisance.