Plutarch, De Iside et Osiride
Goodwin, Ed.

As to sea-fish, they do not all of them abstain from all, but some from one sort, and some from another. As for example, the Oxyrynchites abstain from such as are catched with the angle and hook; for, having the fish called oxyrynchus (the pike) in great veneration, they are [p. 70] afraid lest the hook should chance to catch hold of it and by that means become polluted. They of Syene also abstain from the phagrus (or sea-bream) because it is observed to appear with the approaching overflow of the Nile, and to present itself a voluntary messenger of the joyful news of its increase. But the priests abstain from all in general. But on the ninth day of the first month, when every other Egyptian eats a fried fish before the outer door of his house, the priests do not eat any fish, but only burn them before their doors. For which they have two reasons; the one whereof, being sacred and very curious, I shall resume by and by (it agreeing with the pious reasonings we shall make upon Osiris and Typhon); the other is a very manifest and obvious one, which, by declaring fish to be not a necessary but a superfluous and curious sort of food, greatly confirms Homer, who never makes either the dainty Phaeacians or the Ithacans (though both islanders) to make use of fish; no, nor the companions of Ulysses either in so long a voyage at sea, until they came to the last extremity of want. In short, they reckon the sea itself to be made of fire and to lie out of Nature's confines, and not to be a part of the world or an element, but a preternatural, corrupt, and morbid excrement.