Fish which have fins and scales are kosher. Fish which only have fins are not kosher. Of the four types of scales, clenoid, cycloid, ganoid and placoid, only clenoid and cycloid scales are valid according to the Torah. Gandoid is the type found on sturgeon and placoid is found on shark. There is no prohibition against eating fish blood, other than the fact that people may think that a person is eating prohibited blood, and ritual slaughter is not required.
The scales must be true scales that can be removed without damaging the skin of the fish. As it says in the Torah “These you may eat of the fishes, all that have fins and scales…” (Vayikrah XI:9 12) Bony tubercles and plate or thorn like scales that can be removed only by removing part of the skin are not considered scales in this context.
Some fish that have such scales, such as eels, lump fish, shark, sturgeon, and swordfish, are not kosher. All shellfish and mammals (such as whales, and dolphins) are not kosher. Only the eggs of kosher fish, such as fish roe or caviar, are allowed, therefore supervision is necessary. Care must be taken when buying fresh, whole fish, filleted, or frozen, because of the possibility of substitution by non kosher fish or of contamination by remnants of non kosher fish from knives and cutting boards. Fish sticks have three problems: the fish, the oil, and the frying utensils and equipment (which is usually used for non kosher fish as well as kosher fish).
Smoked fish is frequently soaked in brine and then smoked along with non kosher fish. According to Jewish law, this soaking and smoking is tantamount to cooking over a flame and therefore the product is not kosher. Smoked fish is also often packed in oil, which may not be kosher.
Although herring is famous as a Jewish food, it is not always kosher. The preparation of herring can pose a myriad of problems among which are mono and di-glycerides, non kosher wine vinegar or wine, sour cream, bread crumbs, spices, and equipment contamination.

Kosher Fish

Albacore

Alewife
Amberjack
Anchovies
Angelfishes and butterfly fishes
Atlantic Pomfret or Ray’s Bream
Ballyhoo
Barracudas
Bass , Sea Basses.
Bigeyes
Blackfish
Blacksmith
Blueback
Bluefish or snapper blue
Bluegill
Bocaccio
Bombay duck
Bonefish
Bonito
Bowfin Freshwater dogfish, or grindle
Bream
Brill
Buffalo fishes
Burbot
ButterFishes
Butterfly fish
Cabrilla
Calico
Capelin
Carps and minnows
Carosucker
Caviar (Must be from a kosher fish)
Cero
Channel bass
Chilipepper
Chinook
Chup
Cigarfish
Cisco
Coalfish
Cobia, cabio, or black bonito
Codfishes
Coho salmon
Corbina or Corvina,
Cottonwick
Crapplie
Creville
Croacker
Crucian carp
Cubbyu
Cunner
Damselfishes (
Doctorfish
Dolly Varden
Dolphin (Not Porpoise)
Drums and croakers (
Eulachon
Flounders
Fluke
Flyingfishes and halfbeaks
Frostfish
Gag See
Garibaldi
Giant kelpfish
Gizzard shad
Goatfishes or Gobies (
Goldeye and mooneye (
Goldfish
Grayling
Graysby:
Greenlings
Grindle
Grouper
Grunion
Grunts.
Guavina
Haddock
Hake
Hakes
Halfbeak
Halfmoon
Halibut
Hamlet

Hardhead
Harvestfish
Hawkfishes
Herrings
Hind
Hogchocker
Hogfish
Horse mackerel
Jack Mankerel
Jacks and Pompanos
Jacksmelt
Jewfish
John Dory
KelpSish
Kingfish
Lafayette
Lake Herring
Lance or Launce
Largemouth bass
Lawyer
Leatherback
Lingcod
Lizardfishes
Lookdown
Mackerel
Mackerels, Atka
Mackerels and tunas
Mahimahi
Margate
Menhaden
Menpachii
Merluccio
Milkfish or awa
Mojarras
Mooneye
Mossbunker
Mouthbrooder
Mullet
Muskellunge
Mutton hamlet
Muttonfish
Needlefishes
Opaleye
Palometa
Parrotfishs
Perch
Perches
Permit
Pickerel
Pigfish
Pikes
Pikeperch See: Perches
Pilchard See Herrings
Pinfish See: Porgies
Plaice See: Flounders
Pollock. See: Codfishes
Pomfret. See: Atlantic pomfret
Pompano See: Jack, Butterfishes
Porgies and sea breams (Family Sparidae). Including: Porgies (Calamus species, Diplodus species, Pagrus species); Scup (Stenotomus chrysops); Pinfish (Lagodon rhomboides); Sheepshead (Archosargus probatocephalus)
Porkfish See: Gruntts
Poutassou See: Codfishes
Prickleback See: Monkeyface prickleback, Rockprickleback (non kosher).
Queenfish See: Drums
Quillback See: Suckers
Rabalo See: Snooks
Ray’s bream See: Atlantic pomfret
Red snapper See: Snappers Redfish See: Scorpionfishes, Wrasses
Roach See: Carps Rock bass See: Sunfishes
Rockhind See: Sea basses
Rockfish See: Scorpionfishes. Temperate basses
Rosefish See: Scorpionfishes
Rudderfish See: Sea chubs
Runner See: Jack
Sablefish or black cod (Anoplopoma fimbria)
Sailors choice See: Grunts Saithe See: Codfishes
Salmon See: Trouts
Sand lances, launces, or eels (Ammodytes species)
Sardine See: Herrings
Sargo See: Grunts
Sauger See: Perches
Scad See: Jacks
Scamp See: Sea basses
Schoolmaster See: Snappers
Scorpionfishes (family Scorpaenidae), Including: Scorpionfishes (Scorpaena species); California scorpionfish or sculpin (Scorpaena guttata); Nohus (Scorpaenopsis species); Redfish, rosefish, or ocean perch (Sebasters marinus); rockfishes (Sebasters species, Sebastodes species); Pacific ocean perch (Sebastes alutus); Chilipepper (Sebastes goodel); Bocaccio (Sebastes paucipinus); Shortspine thornyhead or channel rockfish (Sebastolobus alascanus)
Scup See: Porgies
Sea bass See also: Temperate basses, drums, Sea basses (Family Serranidae) including: Black sea basses (Centropristis species); Groupers (Epinephelus species, and Mycteroperca species); Rockhind (Epinephelus adscensionis); Speckled hind (Epinephelus drummondhayi); Red hind (Epinephelus guttatus); Jewfish (Epinephelus itajara); Spotted cabrilla (Epinephelus analogus); Gag (Mycteroperca microlepis); Scamp (Mycteroperca phenax); Graysby (petrometopon cruentatum); Mutton hamlet (Alphestes afer) Sand bass, kelp bass, and spotted bass (Paralabrax species)
Sea bream See: Porgies
Sea chubs (Family Kyphosidae) including: Bermuda chug or rudderfish (Kyphosus sectatrix); Opaleye (Girella nigrican); Halfmoon (Medialuna californiensis)
Seaperch See: Surfperches
Searobins (Family Triglidae); Searobins (Prionotus species)
Seatrout See: Drums, Greenlings, Steelhead
Shad See: Herrings
Sheepshead See: Porgies, Wrasses Sierra See: Mackerels
Silversides (Family Athernidae) including: Whitebait, spearing, or silversides (Menidia species); California grunion (Leurusthes tenuis); Jacksmelt (Atherinopsis californiensis); Topsmelt (Atherinops affinis)
Sirajo goby See: Gobies
Skipjack See Mackerels
Sleeper See Gobies
Smallmouth bass See Sunfishes
Smelts (Family Osmeridae) including: Smelts (Osmerus species); Capelin (Malotus villosus); Eullachon (Thaleichthys pacificus)
Snapper blue See: Bluefish
Snappers (Family Lutjanidae) including: Snappers (Lutjanus species); Schoolmaster (Lutjanus apodus); Muttonfish or mutton snapper (Lutjanus analis); Red snapper (Lutjanus campechanus); Yellowtail snapper (Ocyurus chrysurus); Kalikali (Pristipomoides sieboldi); Opakapaka (Pristipomoides microlepis); Onaga (Etelis carbunculus)
Snooks (Family Centropomidae) including: Snooks orrabalos (Centropomus species)
Sockeye salmon See: Trouts
Sole See also: Flounders
Soles (Family Soleidae), Including: Sole or true sole (solea solea); Lined sole (Achirus lineatus); Hogchoker (Trinectes maculatus).
Spadefishes (Family Ephippidae). Including: Spadefishes (Chaetodipterus species)
Spanish mackerel See: Mackerels
Spearing See: Silversides
Splitttail See: Carps
Spot See: Drums
Sprat See: Herrings
Squawfish See: Carp
Squirrelfishes (Family Holocentridae), Including: Squirrelfishes (Holocentrus species); Menpachii (Myripristis species).
Steelhead See: Trouts
Striped bass See: Temperate basses
Suckers (Family Catostomidae). Including: Buffalo fishes (Ictiobus species); Suckers (Catostomus species, Moxostoma species); Quillbacks or carpsuckers (Carpiodes species)
Sunfishes (Family Centrarchidae). Including: Freshwater basses (Micropterus species); Largemouth bass (Microterus salmoides); Smallmouth bass (Micropterus dolomieui); Sunfishes (Lepomis species); Bluegill (Lepomis macrochirus); Warmouth (Lepomis macrochirus); Rock bass or red eye (Ambloplites rupestris); Crappies or calico basses (Pomoxis species)
Surfperches (Famly Embiotocidae). Including: Surfperches (Amphistichus species, Hyperprosopon species); Seaperches (Embiotoca species, Hypsurus species, Phanerodon species, Rhacochilus species); Blackperth (Embiotoca jacksoni); Pile perch (Rhacochilus vacca); Shiner perch (Cymatogaster aggregata).
Surgeonfishes (Family Acanthuridae). Including: Surgeonfishes and tangs (Acanthurus species, Zebrasoma species); Doctorfish (Acanthurus chirugus); Unicornfishes or kalas (Naso species).
Tang See: Surgeonfishes
Tarpon (Megalops atlantica)
Tautog See: Wrasses
Temperate basses (Family Percichthyidae). Including: Striped bass or rockfish (morone saxatillis); Yellow bass (Morone mississippiensis); White bass (Morojne chrysops); White perch (Morone americana); Giant California sea bass (Stereolepis gigas)
Tench See: Carps
Tenpounder See Ladyfish
Threadfins (Family polynemidae) including: Blue bobo (Polydactylus approximans); Barbu (Polydactylus virginicus); Moi (Polydactylus sexfilis)
Tilapia See: Cichlids
Tilefishes (Family Branchiostegidae) including: tilefish (Logholatilus chamaeleonticeps) Ocean whitefish (Caulolatilus princeps)
Tomcod See: Codfishes
Tomtate See: Grunts
Tomsmelt See: Silversides
Tripletail (Lobotes surinamensis) Trouts and whitefishes (Family Salmonidae) including: Atlantic salmon (Salmo salar); Pacific salmons (Oncorhtnchus species); Coho or silver salmon; sockeye, blueback or red salmon; chinook, king or spring salmon; pink or humpback salmon; chum, dog or fall salmon, Trouts (Salmo species) Brown trout, rainbow trout or steelhead, cutthroat trout, golden trout, Chars (Salvelinus species); Lake trout, brook rout, Arctic char, Dolly Varden, Whitefishes and ciscos (coregonus species and Prosopium species); Cisco or lake herring (Corengonus artedii); chubs (coregonus species); graylings (thymallus Species)
Tuna See: Mackerels
Turbot See Flounder (some non kosher)
Unicornfish See: Surgeonfishes
Wahoo See: Mackerels
Walleye See: Perches
Walleye pollock See: Codfishes
Warmouth See: Sunfishes
Weakfishes See: Drums
WhiteFish See: Trouts, Tilefishes
Whiting See: Codfishes, Hakes, Drums
Wrasses (Family Labridae) including: Hogfishes and aawas (Bodianus species); Hogfish or capitaine (Lachnolaimus maximus); Tautog or blackfish (Tautoga onitis); California sheephead or redfish (Pimelometopon pulchrum); Cunner, chogset, or bergall (Tautogolabrus adspersus)
Yellowtail See: Jacks
Yellowtail snapper See Snappers

Not Kosher Fish

Angler See: Goosefishes
Beluga See: Sturgeons
Billfishes (Family Istiophoridae). Including fishes (Istiophorus species); Marlins and speishes (Tetrapterus species, Makaira species).
BlowEish See: Puffers
Bullhead See: Catfishes
Cabezon See: Sculpins
Catfishes (Order Siluriformes). Including: Channel catfish (Ictalurus punctatus);
Cutlassfishes (Family Trichiuridae) including: Cutlassfishes (Trichiurus species) Scabbardfishes (Lepidopus species)
Dogfish See: Bowfin, Sharks Eels (Order Anguilliforms). Including American and European eel (Anguilia rostrata and Anguila anguila) ; Conger eel (Conger oceanic us) . Gars (Order Semionotiformes). Freshwater gars (Lepisosteus species).
Goosefishes or anglers (Lophius species)
Grayfish See: Sharks
Lampreys (Family Petromyzontidae)
Leatherjacket See: Jacks (Oligoplites saurus)
Lomosuckers (Family Cyclopteridae). Including: Lumpfish (Cyclopterus lumpus); Snailfishes (Liparis species).
Marlin See: Billfishes
Midshipman See: Toadfishes
Ocean pout or eelpout (Macrozoarces americanus)
Oilfish (Ruvettus pretiosus) Puffers (Family Tetraodontidae).
Paddlefish See: Sturgeons
Pout See: Ocean pout
Puffers, blowfishes, swellfishes, sea squab (Sphoeroides species)
Ratfish See: Sharks
Ray See: Sharks
Rock prickleback or rockeel (Xiphister mucosus)
Sailfish See: Billfishes
Sculpins (Family Cottidae). Including: Sculpins (Myoxocephalus species, Cottus species, Leptocottus species, etc.). Cabezon (Scorpaenichthys marmoratus); Searaven (Hemitripterus americanus)
Searaven See: Sculpins Sea squab See: Puffers
Sharks, rays and their relatives (Class Chondrichthyes). Including Grayfishes or dogfishes (Mustelus species, Squalus species); Soupfin shark (Galeorhinus zyopterus); Sawfishes (Pristis species); Skates (Raja species); Chimaeras or ratfishes (Order Chimaeriformes).
Skates See: Sharks
Snake mackerels (Gempylus species)
Spoonbill cat See: Sturgeons
Sturgeons (Order Acipenseriformes). Including: Sturgeons (Acipensen species, Scaphirhynchus species); Beluga (huso uso); Paddrefish or spoonbill cat (Polyodon spathula)
Swordfish (Xiphias gladies)
Toadfishes (Family Batrachoididae). Including: Toadfishes (Opsanus species); Midshipment (Porichthys species).
Tiggerfishes and firefishes (Family Balistidae). Triggerfishes (Balistes species, Canthidermis species)
Trunkfishes (Family Ostraciidad). Trunkfishes and cowfishes (Lactophrys species). WolEshes (Family Anarhichadidae). Including: Wolffishes or ocean. catfishes (Anarhichas species)