In esoteric writings, the fish symbol is the most used one. The fish which Jonah was lived in and Moses forgot / lost it on his journey and Jesus fed the five thousands with. It’s complicated to understand the symbolic meanings of fish because the fish moves nondirectional and random and also is an absentminded and aimless.

Maybe that’s why the fish symbol is the best one to reflect human because just like the heedlessness of man, the fish is unaware of the ocean.
In the world of symbolism the fish involves every situation of human being, every dress a man puts on. Fish symbolizes the human body. The swimming sperma in the beginning and also the fetus in uterus is a fish.The brain swims in salted water is also a fish. The tongue in mouth is such as a fish like the Messiah figured in as a snake in heaven. Swimming stars in circle are each like fishes or the thoughts are the fish of Quantum sea.

There are too many people with different types of intentions. The pilgrims when they circumambulate the Kaaba are like swimming fishes with their intents.
Certainly there are many fish in the ocean but the masters of the Ancient Wisdom say : “only the ones who hooked by the angling man will have the ability for being human.