What seafood can kosher eat? A definitive guide

November 18, 2025 •

3 min read

According to Jewish dietary law, only aquatic creatures with both fins and easily removable scales are permitted. This fundamental principle defines what seafood can kosher eat, strictly excluding all types of shellfish and creatures like eels, sharks, and marine mammals.

Quick Summary

Kosher dietary laws dictate that only fish possessing both fins and easily removable scales are permissible for consumption, excluding all shellfish and other creatures lacking these features.

Key Points

Fins and Scales Rule: For seafood to be kosher, it must possess both fins and easily removable scales, a rule rooted in biblical law.
Shellfish is Excluded: All shellfish, including shrimp, lobster, and crab, are strictly forbidden because they lack the required fins and scales.
Scales Must Be Removable: A kosher scale must be visible and detach from the fish's skin without causing damage, which is why fish like sturgeon are non-kosher.
Certification is Crucial for Processed Fish: Canned, smoked, or filleted fish often require reliable kosher certification to ensure proper handling and to avoid cross-contamination from non-kosher processing.
Check Fish with Fewer Scales: While some fish like tuna may have sparse or shed scales, they are recognized as kosher by tradition, but caution is still required when purchasing.
Pareve Status: Kosher fish is considered pareve (neutral) and can be consumed with either meat or dairy products, though some traditional practices suggest separation from meat.
Avoid Catfish, Eel, and Shark: Common non-kosher species include catfish, eels, and sharks, as they do not meet the fin and scale requirements.

The Golden Rule: Fins and Scales

The foundation of kosher seafood lies in the biblical injunction found in Leviticus 11:9-12 and Deuteronomy 14:9-10, which explicitly states that only sea creatures with both fins and scales are fit for consumption. Any creature lacking either of these two characteristics is considered non-kosher, or treif. This simple rule immediately eliminates entire classes of aquatic life from the kosher diet.

The Nuance of Scales

While the concept of fins is straightforward, the definition of a "kosher scale" is more specific than its scientific counterpart. According to Jewish law, a scale must be visible to the naked eye and easily removable from the fish's skin without damaging the flesh. This is why certain fish, such as sturgeon and swordfish, are generally considered non-kosher by most Orthodox authorities, despite having some form of scales or possessing them at an early life stage. Their scales are either too embedded or fall off before they are harvested.

Why Shellfish are Forbidden

Perhaps the most well-known exclusion in kosher seafood is shellfish. This is not simply a matter of tradition but a direct consequence of the fins and scales rule. Crustaceans like shrimp, crab, and lobster, and mollusks such as clams, oysters, and mussels, do not possess fins or scales, rendering them forbidden. This prohibition extends to all variations of these creatures, regardless of how they are prepared.

Purchasing and Preparing Kosher Fish

For observant individuals, buying fish requires careful consideration, especially in markets that are not under rabbinical supervision.

Here are key steps to ensure kashrut when buying fresh fish:

Buy Whole: The safest method is to purchase the fish whole, allowing you to visibly confirm the presence of both fins and easily removable scales.
Check Fillets: If buying fillets, ensure they are purchased from a kosher-only fish store or have a piece of skin with scales still attached. Relying on a sign alone is insufficient.
Certifications for Processed Fish: Canned, smoked, or processed fish products like tuna and sardines require a reliable kosher certification (hechsher). This ensures the fish was processed on kosher equipment and that all ingredients, including flavorings and oils, are kosher.
Prevent Cross-Contamination: When using a non-certified fish counter, ask the fishmonger to thoroughly wash the knife and cutting board before preparing your fish. Some strict observers even prefer to bring their own knife and board.

Common Kosher vs. Non-Kosher Seafood


Feature	Kosher Fish Examples	Non-Kosher Seafood Examples
Fins & Scales	Yes	No
Classification	True bony fish	Shellfish, sharks, marine mammals
Common Types	Salmon, Tuna, Cod, Halibut, Tilapia, Trout, Flounder, Herring	Shrimp, Crab, Lobster, Oyster, Clam, Squid, Octopus, Eel, Catfish, Shark
Market Purchase	Whole fish or certified fillets	None permitted
Roe (Eggs)	Kosher if from a kosher fish; often requires certification unless naturally red/pink	Always non-kosher, no exceptions

The Case of Tuna and Salmon

While some fish, like tuna and salmon, have few scales or can shed them when caught, they are considered kosher. In the case of tuna, rabbinic tradition confirms its kosher status. For salmon, the distinct pinkish-red flesh is recognized by many authorities as a reliable indicator, even when purchasing skinless fillets. However, as mentioned, canned or processed tuna and salmon still require kosher certification due to processing concerns.

A Final Note on Kashrut

Fish is classified as pareve, meaning it is neither meat nor dairy. While it can be eaten with either, some rabbinic traditions historically advise against mixing fish with meat at the same time. For the modern consumer, understanding the core principles of fins and scales empowers one to navigate the market and make informed, kosher-compliant choices.

Conclusion: Navigating the Kosher Seafood Market

Ultimately, adhering to kosher dietary laws for seafood comes down to a clear, biblically-based rule: the presence of both fins and easily removable scales. This guidance provides a simple framework for determining which fish are permissible, while also highlighting the importance of cautious purchasing, especially for processed or filleted products that could be subject to misidentification or cross-contamination. By understanding these rules and seeking out certified products when necessary, one can confidently enjoy a wide variety of delicious and permissible fish.

For further reading and resources on kosher laws, a great starting point is the comprehensive information provided by authoritative sources like Chabad.

Frequently Asked Questions

No, not all fish are kosher. According to Jewish dietary law, only fish that have both fins and easily removable scales are permitted for consumption.

Shellfish like shrimp, lobster, crab, and clams are not kosher because they lack the fins and scales required by Jewish law for aquatic creatures to be permissible.

Yes, but canned tuna requires reliable kosher certification. While tuna itself is a kosher fish, the processing and other ingredients used in the canned product must also be kosher to ensure its status.

Buying skinless fillets is problematic unless from a supervised kosher fish store. Without the scales attached, it is difficult to verify the fish's kosher status.

Yes, salmon is a kosher fish because it has fins and scales. Many authorities also accept its naturally pink-red flesh as an identifying characteristic when buying skinless fillets.

Fish eggs or roe are only kosher if they come from a kosher fish. Therefore, caviar must have reliable kosher certification to ensure it originated from a permissible species.

Sturgeon and swordfish are typically not considered kosher by most Orthodox authorities because their scales are either too difficult to remove or are lost during their lifecycle, failing to meet the specific definition of kosher scales.