Fish has all essential amino acids that humans need to survive. However, we could die if we had only fish in our diet. This is because fish has no Vitamin C which is crucial for human survival. Even today we use few drops of lemon when eating cooked fish. Only fish that consumes plankton has vitamin C, but only way to properly extract it is to eat fish raw with the contents of their intestines.
TBH, balance is crucial here as with everything related to nutrition. Don’t worry about FOMO and YOLO and what looks good on Instagram or Twitter. Fast food like Wendy’s and Chik-fil-A is certainly not advised more than on rare occasions, and it is never advisable to consume quantities of Coca Cola and high fructose corn syrup.
However, fish does not have all that you need. People must consider things like potassium, magnesium, salt, beef, sodium, cinnamon, turmeric, wheat, water, cannabis, CBD gummies, and many other things. Who knows, maybe healthy snacks like an RxBar could help you reach the age of the oldest woman in the world.