The above lines “Every eel hopes to be a whale” expresses that a every person in this world have some desires, some are in his hands some are not. The one which are not in his hands are his wishes. These wishes are reachable with strong efforts and some kind of ambition to achieve them. Ambitions are strong desires which are helpful in achieving the wishes. The above line states that everyone in this world wants to live a luxurious life but when he got that he wants more enough than that. His wishes never comes to an end and he wants to be a whale means that he wants to be big enough that no one could reach him.
Here, big means not a healthy body but desirable and a luxurious life and here eel means a person who is a poor personality who cannot even fulfil his basic needs. In fact, eel is a smallest fish in a ocean whereas whale is the largest fish in the world. In these lines, eel is being expressed as a person who cannot fulfil his basic needs and whale is being expressed as a person who leads a happy and a luxurious life. One should be like that but to choose a reasonable way not a devilish way if he chooses those ways he might be escaped in this world but in the next world he will be punished harshly by ALLAH Almighty.