Jewish Food/Is tuna kosher


I understand that tuna has scales and fins, but are the scales easy to remove? And also flatfish (flounder) they have scales on one side, are they kosher? Do scales keep the fish from getting parasites, is this what keeps them CLEAN?

Hi Anita,

The whole body of a Kosher fish does not have to be covered with scales. If the scales are only by the gills, fins or tail, this is sufficient. The size, and thickness of the scales are irrelevant. The scales must be round or comblike in shape, and not platelike or armorlike (which is why Sharks and Sturgeon aren't Kosher). Flounder is a Kosher fish. Tuna is a Kosher fish, but depending on how it's processed it might not be Kosher.  Also, fish other than Tuna are sometimes labeled as being Tuna. The most popular Kosher Tunas include Skipjack, Albacore, Bluefin and Yellowfin. This is when buying from a certified Kosher fish market would be helpful.
To be sure that a fish is Kosher, check for fins and scales (scales must be removable either by hand or with a knife without ripping the underlying skin. Flounders (including other flat fish: Halibuts,  certain varieties of Turbot, Fluke, Brill, Plaice and Sole) are all Kosher fish.

Scales do not prevent a fish from picking up parasites. Fish that feed and live on the bottom of the ocean, such as Flounder can indeed have worms. Fish fillets can be put on a light table and checked for worms. Most fish are worm free. Many times, the food the fish eats contains parasites, and some of these worms will work their way through the intestines and into the flesh of the fish. The Talmud explains that insects found in the stomach are presumed to have been swallowed by the fish and originate from the outside of the fish, rendering it non-kosher, while those found inside the flesh had grown inside the fish itself and are not considered "Shrotzey Hayam" (insects of the ocean) until they exit the fish (but personally, I'd reject any fish with visible worms).
It is common to find worms inside the stomach & flesh of a number of different fish. When removing the internal organs of a fish one, should be very cautious to remove the entire intestines in one piece & rinse the fish very well. Not all of the parasites in the flesh will have originated on the inside, some may have originated in the flesh itself. Most people who keep Kosher do not have to worry about parasites in the fish as long as one cleans the inside of the fish well before cutting it up.

Keeping the fish wet until it's time to scale it helps make removing the scales easier. Tuna has fewer scales than some other fish, their scales can be easily removed. Read more at:

There are fish scaling tools you can use, if using a butter knife isn't working for you. Here is an example of a fish scaling tool:

Here are directions for how to scale a fish:

I hope I've been a help.
Best of luck,


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