Newly added fish do not recognize their "loot_table"!

When they (the fish) died, I realized that their items did not fall. So I changed the name of cod's loot_table from "cod_mob" to "cod".
Then they began dropping items.
Is it a bug that the name was wrong and not working properly?
(Only "Tropical _ fish" was not improved, despite its name being the same.)

※I am translating from Japanese to English using a translation machine