remember the saying you are what you eat!!! this is the fact when it comes to the dietary needs of cornivores each type of food you offer you fish will be a source of a small portion of its dietary needs as each species of food has its own dietary needs which will be passed down by consumption.. keeping a varied diet ensures your fish will get the proper nutrients it needs to grow and be healthy,, no one food will cover everything that is needed for a carnivores health...as for my eels I have always fed them squid, shrimp ,scallops, salmon(<not very often as it is a fatty fish)halibut.silverslides ,frozen krill. thaw all food in fw to kill off any worms or parasites that may be harbored in them b4 feeding.. as transmitting them to your fish... not all will die from freezing.