Why is sev a fish?

"Sev" is not a fish. It is a type of crunchy, savory snack popular in Indian cuisine. It's made from chickpea flour (besan) and sometimes other ingredients like rice flour, spices, and herbs.

There seems to be a misunderstanding. Perhaps you were thinking of another word?

If you can give me more context or details about what you were thinking of, I can try to help further.