List of halal and kosher fish

This is a list of fish that are considered both halal, by Muslims according to sharia, and kosher, by Jews according to halakha.
In Sunni Islam, there are two general schools of thought. Most Sunni Muslim schools of jurisprudence (Shafi'i, Hanbali, and Maliki) hold as a general rule that all "sea game" (animals of the sea) are permissible to eat with a few minor exceptions. Thus, for example, the local dish Laksa (which includes meats such as shrimp and squid with a soup base made from shrimp paste), is deemed permissible in the Shafi'i Sunni Muslim majority nations of Indonesia and Malaysia where it is commonly consumed.
In the Hanafi school, one of the four Sunni schools, only "fish" (as opposed to all "sea game") are permissible, including eel, croaker and hagfish.
Any other sea (or water) creatures which are not fish, therefore, are also makruh tahrimi (forbidden but not as the same level as haram) whether they breathe oxygen from water through gills (such as prawns, lobsters and crabs, which are crustaceans), molluscs such as clams, octopus, mussels and squid, especially if they breathe oxygen from air through lungs (such as sea turtles and sea snakes which are reptiles, dolphins and whales which are mammals, or semi-aquatic animals like penguins which are birds, saltwater crocodiles which are reptiles, seals which are mammals, and frogs which are amphibians).
However, in the Hanafi school of thought, there is a difference of opinion regarding whether or not shrimp and prawns are fish or not. Those who say they are halal say that the Arabs used to consider them fish, thus permissible. Whereas others state that prawns and shrimps are not actually fish nor do they look like one so shrimps and prawns are not permissible. Also the hanafi scholars prohibit fish which died of natural causes and starts to float on the surface of the water (also known as Samak-al-Tafi).
Under the Ja'fari jurisprudence followed by most Shia Muslims (including most Twelvers and Ismailis, the largest extant Shia sects), only certain fish are considered permissible for consumption. Any fish without scales are haram (forbidden) but fish that do have scales are permissible. Shia scholars tend to teach that no other aquatic creatures are halal, with the exception of certain edible aquatic crustaceans (e.g. shrimp but not crab), which are also Halal like scaled fish.
The Ja'fari Shia Islam rules are approximately equivalent to kashrut rules. The two are generally the least inclusive:
All fish in this article have true (visible) fish scales, an endoskeleton, fins, and gills (as opposed to lungs). The requirement for gills is not part of any religious rule, but biologically it is an identifying characteristic of true fish. Any animal lacking any of the latter three features is not a fish, and is therefore not valid for this article.
The rules are relaxed in some Islamic schools of thought, both Shia and Sunni. Some have looser definitions which include the exoskeleton of crustaceans as "scales", others yet include the softer exoskeletons of prawns as "scales" but exclude the harder exoskeletons of lobsters. They also differ in the definition of fish, some adopting a loose definition to include all water life ("sea game").
According to the chok or divine decrees of the Torah and the Talmud, for a fish to be declared kosher, it must have scales and fins.
The definition of "scale" differs from the definitions presented in biology, in that the scales of a kosher fish must be visible to the eye, present in the adult form, and can be easily removed from the skin either by hand or scaling knife.
Thus, a grass carp, mirror carp, and salmon are kosher, whereas a shark, whose "scales" are microscopic dermal denticles, a sturgeon, whose scutes cannot be easily removed without cutting them out of the body, and a swordfish, which loses all of its scales as an adult, are all not kosher.
When a kosher fish is removed from the water, it is considered "slaughtered", and it is unnecessary to ritually kill it in the manner of kosher livestock. However, kosher law explicitly forbids the consumption of a fish while it is still alive.
Although Joseph Karo of Safed, in his 16th-century legal commentary the Beit Yosef, considers eating milk and fish together to be a health risk, Karo does not mention a prohibition of eating dairy and fish together in the Shulchan Aruch.
Most rabbinic authorities from that time onwards, including almost all Ashkenazi ones, have ruled that this was a scribal error, and there is neither Talmudic basis nor any other rabbinical precedent for prohibiting milk and fish, and thus permit such mixtures. Indeed, two passages in the Babylonian Talmud implicitly state that it is entirely permissible.
Nevertheless, since Karo and other rabbis wrote that milk and fish should not be mixed, there are some Jewish communities whose practice is not to mix them. The Chabad custom is not to eat fish together with actual milk, but to permit it where other dairy products are involved, so that adding a touch of butter or cream to the milk is sufficient to permit mixing it with fish.