They;ll eat the tiny bloodworm (I usually sift through my mozzie bucket and grab the bloodworms out of the bottom). You should see if you can get some daphnia, or if you have any bloodworm larvae (midge/sandfly larvae) chances are you'll find tiny mozzy larvae which they also eat.
As long as you do daily waterchanges and make sure not to put too much in, you soon get the hang of how much they need to eat or not. I do prefer feeding the mozzy larvae, daphnia and bloodworm but find with our cold spell it's easier dealing with hatching brineshrimp inside. I keep bbs in a separate container (after rinsing of brine and they last about 4 days)
If yours do have eggs , you don't have to raise them, you could sell/give away the eggs or leave them in the tank.