This section is from the book "Legendary Fictions Of The Irish Celts", by Patrick Kennedy. Also available from Amazon: Legendary Fictions of the Irish Celts.
A long time ago there was a well in Ossory, shaded by a rowan-tree. When the berries became ripe they would drop into the water, and be eaten by the salmon that had their residence in the well. Red spots would then appear on the fish, and they received the name of " Salmon of Knowledge." It was not so easy to take these salmon, for there were shelving banks, and they could also retreat into the cavern from which issued the waters that supplied the well. However, one was occasionally caught, and the captor, so soon as he had made his repast on it, found himself gifted with extraordinary knowledge, even as Fion, son of Cumhail, when he had tasted of the broiled salmon of the Boyne. It was understood that no woman could taste of this delicacy and live. Yet Sionan, a lady cursed with an extraordinary desire of knowledge, braved the danger, suspecting the report to be spread abroad and maintained by the male sex from merely selfish motives. So, in order to lose no time, she had a fire ready by the side of the well, and the unfortunate fish was scarcely flung out on the herbage when he was disembowelled and frying on the coals. Who can describe the rapture she felt from the burst of light that filled her mind on swallowing the first morsel! Alas ! the next moment she was enveloped by the furious waters, which, bursting forth, swept westwards, and carried the unfortunate lady with them, till they were lost in the great river which ever after bore her name.
Legends of foreign lakes afford an occasional parallel, not in detail, but in the idea of a supernatural origin, to these wild stories of our own. The following one, borrowed from Denmark, being curious, we give it welcome as a specimen :-
 
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