Tuna, for example, have very few scales, yet is kosher. Other popular kosher fish are bass, carp, cod, flounder, halibut, herring, mackerel, trout and salmon. Crustaceans (such as lobster and crab) and other shellfish (such as clams) are not kosher, because they lack scales.

Which fish do not have scales?

Fishes that don't have scales include the clingfish, catfish and shark family, among others. Instead of scales, they have other layers of material over their skin. They can have bony plates that are also covered by another layer or tiny, teeth-like protrusions covering their skin.

Is cod fish kosher?

Salmon, trout, tuna, sea bass, cod, haddock, halibut, flounder, sole, whitefish, and most other fish commonly available in markets are kosher. Shellfish, mollusks, and squid aren't kosher. Monkfish, which doesn't have scales, isn't kosher.