Are there any Church traditions or legends that state what species of fish Tobias caught in the Book of Tobit? Are there any Church traditions or legends that state what species of fish the young man Tobias caught in the Book of Tobit according to the Catholic, Orthodox or other local churches of the East?


  The Book of Tobi is a book of scripture that is part of the Catholic and Orthodox biblical canons, pronounced canonical by the Council of Hippo (in 393), Councils of Carthage of 397 and 417, Council of Florence (in 1442) and confirmed for Roman Catholics by the Council of Trent (1546). - Book of Tobit (Wikipedia)


Here is what the Book of Tobit has to say about Tobias and the fish:


  1 And Tobias went forward, and the dog followed him, and he lodged the first night by the river of Tigris. 2 And he went out to wash his feet, and behold a monstrous fish came up to devour him. 3 And Tobias being afraid of him, cried out with a loud voice, saying: Sir, he cometh upon me. 4 And the angel said to him: Take him by the gill, and draw him to thee. And when he had done so, he drew him out upon the land, and he began to pant before his feet. 5 Then the angel said to him: Take out the entrails of the fish, and lay up his heart, and his gall, and his liver for thee: for these are necessary for useful medicines. 6 And when he had done so, he roasted the flesh thereof, and they took it with them in the way: the rest they salted as much as might serve them, till they came to Rages the city of the Medes. - Tobit 6: 1-6.


The Jewish Encyclopedia states that the Book of Tobit is was probably composed between 200 and 50 B.C.
Anchor Bible by Lopukhin (Толкование на книгу Товита) says that some people attribute it to "sabot" or "alsabut" in Arabic language, others think it is pike. The latter is especially due to the fact that pike is common among Jews and is a clean fish.

Please note that the success of usage of that fish was not due to the nature of the fish itself, as noted in that Anchor Bible later, but due to the prayer, as note A. Glagolev and Prof. Drozdov in the cited works.