I am sure the Eels are ok. They do sometimes starve, but like a previous person said, they eat at night, and eat the scraps of food you feed to the other fish. They find food. You should try to "hand feed" the eel. I got my eel to eat out of my hand slowly. I first dropped the blood worms by their head, because at first you can't get too close. Then after they start eating it, you actually slowly hand feel them. My eel now eats out of hand, and is very happy. He is a glutten, and comes out all the time, hoping I will feed him. Here is my eel in his new tank, haming it up with the other gluttonous fish in my tank. It takes time, but it should eat out of your hand, if you slowly wein them onto the blood worms by hand.
Also, you do have a lot of eels, and I wouldn't be surprised if a few might die off. It is usually not recommended to keep more than one in a tank (but that never stops us when we buy other species of fish). My fire eel here killed my eel that you have (the same type as yours got killed). There might be infighting that you don't see.

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