§ Yalta said to her husband Rav Naḥman: Now as a rule, for any item that the Merciful One prohibited to us, He permitted to us a similar item. He prohibited to us the consumption of blood, yet He permitted to us the consumption of liver, which is filled with blood and retains the taste of blood...It is prohibited to eat pork, but one may eat the brain of a shibuta fish, which has a similar taste...I wish to eat a dish that tastes like meat cooked in milk.

You shall not plow with an ox and a donkey together.

The Sage Raḥava raises a dilemma: With regard to one who drives a wagon with a goat and a shibbuta, what is the halakha? Has he violated the prohibition against performing labor with diverse kinds? Do we say that since the goat does not descend into the sea and the shibbuta does not ascend onto the land, they are not working together at all, and so he has not done anything forbidden? Or perhaps, since in any event, he is now driving the wagon with both of them, he thereby transgresses the prohibition?

One who drives with an animal on the shore of the sea and a particular fish, and the fish was in the sea and the animal was on the ground on its shore and they were attached with one rope such that both were pulling; [the ruling] is uncertain and it is forbidden, but if one did it they are exempt.

The Sages taught in a baraita (Tosefta, Kilayim 5:10): For every animal that exists on land there is an equivalent animal in the sea, except for the weasel, which exists only on land...

In Kiddushin (41a) it says "Rava salted a shibuta" - and this is the goat of the sea, as it says in chapter 5 of Bava Kamma (55a) "one who drives a wagon with a goat and a shibbuta..."

Rav Safra relates: Once we were traveling on a ship and we saw a certain fish that took its head out of the sea, and it had horns, and the following was inscribed on them: I am a lowly creature of the sea and I am three hundred parasangs long, and I am going into the mouth of the leviathan. Rav Ashi said: That is the goat of the sea, which searches through the sea and has horns.

Abaye said: Hide, fish, and a cup, hot water, and eggs, and white lice all cause the other matter, i.e., leprosy. The Gemara elaborates: Hide is referring to one who sleeps on a tanner’s hide before it has been tanned. Fish is referring to the shibuta fish in the days of Nisan. The cup is referring to one who eats the leftovers of small fried fish. Hot water is referring to very hot water that one pours on himself. Eggs means one who steps on eggshells. White lice is referring to one who washes his garment but does not keep it for eight days before wearing it again, a habit which creates these lice. And all of these practices cause the other matter, leprosy.

Rebbi Ḥanina the son of Rebbi Abbahu said, 700 kinds of pure fish and 800 kinds of pure locusts and innumerable birds all were exiled with Israel to Babylonia; and when they returned, all of them returned, except the fish called shibuta. How did fish migrate? Rebbi Ḥuna bar Joseph said, they went into exile through the abyss end returned through the abyss.

Rabbi Ya’akov said that Rabbi Yoḥanan said: They all returned except for the kolyas ha’ispanin, as Rav said: Those inclines of Babylonia return the water through underground watercourses to the spring of Eitam in Eretz Yisrael, and the fish also returned through these watercourses. And this fish, the kolyas, because its spine is not strong, it could not ascend these watercourses and did not return to Eretz Yisrael.

Ispanin [From the country of Spain].

kolyas ha’ispanin means a fish from areas surrounding Spain. And its name in arabic is al shabut. And in the holy tongue it is shibuta and in Rabbinic parlance it is kufya, as iin "the bile of a kufya" (Pesachim 39a). And some say that it is tuna.

Except for old salted fish kolyas ha’ispanin - A fish which is called tuna.

We must say that there are many types of shibuta.