Worms in fish
In halachah seforim, a distinction is made between two types of worms in fish:
Type 1. Worms that are found on the outside of the fish’s skin, inside the head, or in the belly cavity. All these worms are ossur – prohibited.
Type 2. Worms that are inside the flesh of the fish or between the skin and the flesh. These worms are permitted according to halachah. (See Shulchan Aruch Y.D. 84:16 and see explanation in the sefer Bedikas HaMazon K’Halacha in Hebrew, Vol. 1, halachah section, Chapter 3, paragraph 6.)
Today’s poskim are considering whether or not the anisakis worm is included in the halachic category of “worms in the flesh of fish.”
ocean fish
[level h3=”1. External infestation ” gen=”4″ gb=” us=” il=”]
With most ocean fish, there is usually no external infestation.
Exceptions: On salmon, sole, and ocean trout, there are sometimes brown parasites on the skin (salmon lice). They are easy to see and easily removed by rubbing (Illustration 88).
On redfish (rotbarsch) it is common to find a certain kind of worm which is hard to remove. We therefore recommend not using this fish (Illustration 87).
[level h3=”2. Infestation in the belly cavity ” gen=”3″ gb=” us=” il=”]
Worms are found in the belly cavity of whole or sliced ocean fish (Illustrations 83, 251, 252)
After cleaning the fish, one should carefully examine the inner wall of the belly cavity and along the spine (the central bone along the inner side of the belly cavity), looking for thin worms, which look like little snakes curled up around themselves.
If worms are found, scrape the inside of the belly cavity with a knife or hard nylon brush, rinse well, and check to make sure that all the worms were removed.
Ocean fish fillets (without bones and without the belly flaps) usually do not have the worms that were in the belly cavity.
List No. 1
Fish that are prone to infestation in the belly cavity
- Anchovy
- Cod
- Flounder
- Haddock
- Hake [attr tag=’small’](Bakalah*)[attr tag=’/small’]
- Halibut
- Herring [attr tag=’small’](Matjes – whole pickled herring)[attr tag=’/small’]
- Ling
- Little Tuna [attr tag=’small’](Palamida)[attr tag=’/small’]
- Mackerel
- Plaice
- Pollock [attr tag=’small’](Zaavon)[attr tag=’/small’]
- Red Drum Fish [attr tag=’small’](Musar – from the ocean)[attr tag=’/small’]
- Red Perch
- Red Snapper [attr tag=’small’](Farida)[attr tag=’/small’]
- Red fish [attr tag=’small’](Rotbarsch)[attr tag=’/small’]
- Salmon – wild [attr tag=’small’](from Alaska, China, Japan)[attr tag=’/small’]
- Sable
- Sardines
- Sea Bass [attr tag=’small’](Chilean, Lavrak)[attr tag=’/small’]
- Scrod
- Sprats
- Sole
- Trout [attr tag=’small’](from ocean)[attr tag=’/small’]
- Tuna
- Turbot
- White fish
- Whiting*
[attr tag=’small’]Note: In whiting (Bakalah tza’ir), which is sold as a whole fish, there is a great deal of infestation in the belly cavity. The worms are hard to remove, and therefore the use of this fish is not recommended.[attr tag=’/small’]
[level h3=”3. Infestation in the flesh of the fish ” gen=”3″ gb=” us=” il=”]
Most ocean fish, such as those listed above (List No. 1), have various worms in the flesh. See above for halachic opinions concerning them.
There is no sure way of removing all the worms from the flesh of the fish, so that even when the package states that the fish inside have been checked for worms, they cannot be presumed to be totally free of worms.
List No. 2
Ocean fish that do not have worms in their flesh
Gilt-Head Sea Bream [attr tag=’small’](Denis)[attr tag=’/small’]
Grouper [attr tag=’small’](Lokus, Jaffa fish)[attr tag=’/small’] – only fresh
Nile Perch [attr tag=’small’](Nesichat haNilus)[attr tag=’/small’]
Red Mullet [attr tag=’small’](Barbunia)[attr tag=’/small’]
Salmon — farm-raised [attr tag=’small’](from Norway, Scotland and Chile)[attr tag=’/small’]
Sea Bass [attr tag=’small’](Lavrak)[attr tag=’/small’] – farm-raised
Shibrum [attr tag=’small’](Corbina)[attr tag=’/small’]
Tuna [attr tag=’small’](only the light parts without the belly flaps, such as frozen tuna slices and canned tuna).[attr tag=’/small’]
[level h3=”4. Roe of ocean fish ” gen=”3″ gb=” us=” il=”]
Heavily infested. Their use is not recommended. Includes: herring roe, hake (bakalah) roe, etc. (Illustration 253).
Salmon roe from farmed fish (e.g. from Norway) is clean.
[level h3=”5. Heads of ocean fish ” gen=”1″ gb=” us=” il=”]
In general, there is no infestation in the heads of ocean fish.
An exception is salmon heads. They may harbor “salmon lice.” Cut the head in half, remove the gills, and inspect well (Illustration 254).
pond fish
1. External infestation
[level h3=” A. Lernaea (“anchor worms”) ” gen=”5″ gb=” us=” il=”]
Pond fish are liable to harbor white or gray worms, “lernaea,” on their skin. These worms can be identified by the red wound which they cause on the fish’s skin, with a gray thread-like piece coming out of it (Illustrations 91, 255). The entire infested area should be removed. (When the lernaea is young, it is hard to notice it.)
It is recommended that when one wants to use pond fish, one should buy it in a store with a mehadrin hashgachah.
List No. 3
Fish that may harbor lernaea
- Barramundi [attr tag=’small’](Sea Perch)[attr tag=’/small’]
- Carp
- Grass Carp [attr tag=’small’](Amur)[attr tag=’/small’]
- Gray Mullet [attr tag=’small’](Burri)[attr tag=’/small’]
- Kinneret Sardines
- Silver Carp [attr tag=’small’](Kassif)[attr tag=’/small’]
- Striped Bass [attr tag=’small’](Bass)[attr tag=’/small’]
- Tilapia-Fresh [attr tag=’small’](Amnon, Admonit, St. Peter’s Fish)[attr tag=’/small’]
[level h3=” B. Argulus” gen=”5,3″ gb=” us=” il=”]
Some pond fish are liable to harbor “argulus”, a small transparent parasite which is very hard to see. The sea parasites stick to the fish’s skin and inside the head (Illustrations 6, 90, 256).
Fish farmers must take special precautions to rid their ponds of these parasites. In some of the marketing centers, there is a supervisor whose job it is to make sure that the pond treatment has been done properly. If the fish was bought in a store with a mehadrin hashgachah, it is enough to rinse the fish well before use.
For fish that is bought without a hashgachah and fish from the Kinneret, discard the head, fins, and tail, then scrape the entire surface of the skin well with a knife, and rinse well.
It’s best to freeze the fish before doing this cleaning. (Freezing causes the parasites to loosen their hold, making them easier to remove.) If the skin is removed, the fish may be eaten without cleaning.
Carp in the United States is presumed clean.
List No. 4
Fish that may harbor argulus
Carp
Grass Carp [attr tag=’small’](Amur)[attr tag=’/small’]
Silver Carp [attr tag=’small’](Kassif)[attr tag=’/small’]
List No. 5
Pond fish that are presumed to be clean externally and internally
Red Drum [attr tag=’small’](Musar)[attr tag=’/small’]
Tilapia – Frozen Tilapia fillets [attr tag=’small’](Amnon)[attr tag=’/small’] imported from China are clean.
Trout – Local trout [attr tag=’small’](from Eretz Yisroel)[attr tag=’/small’] may be presumed clean. In frozen imported trout there are sometimes brown parasites on the skin of the fish [attr tag=’small’](salmon lice)[attr tag=’/small’]. They are easily visible and come off when scraped [attr tag=’small’](see “Ocean Fish – External infestation”)[attr tag=’/small’].
2. Internal infestation
Infestation is usually not present in the belly cavity and in the flesh of pond fish.
3. Roe of pond fish
The roe of pond fish does not harbor infestation.
[level h3=”4. Heads of pond fish ” gen=”2″ gb=” us=” il=”]
Argulus or lernaea parasites may be found in the heads of carp, gray mullet (burri), silver carp (kassif), and striped bass. Only heads of fish that are sold with a mehadrin hechsher should be used.
