THE gods were so angry with Loki that he had to run away and hide himself in the mountains, and there he built a house which had four doors, so that he could see around him on every side. He would often in the day-time change himself into a salmon and hide in the water called Franangursfors, and he thought over what trick the gods might devise to capture him there. One day while he sat in his house, he took flax and yarn, and with it made meshes like those of a net, a fire burning in front of him. Then he became aware that the gods were near at hand, for Odin had seen out of Hlidskjalf where he was. Loki sprang up, threw his work into the fire, and went to the river. When the gods came to the house, the first that entered was Kvasir, who was the most acute of them all. In the hot embers he saw the ashes of a net, such as is used in fishing, and he told the gods of it, and they made a net like that which they saw in the ashes. When it was ready they went to the river and cast the net in, Thor holding one end and the rest of the gods the other, and so they drew it. Loki travelled in front of it and lay down between two stones so that the net went over him, but the gods felt that something living had been against the net. Then they cast the net a second time, binding up in it a weight so that nothing could pass under it. Loki travelled before it till he saw the sea in front of him. Then he leapt over the top of the net and again made his way up the stream. The gods saw this, so they once more dragged the stream, while Thor waded in the middle of it. So they went to the sea.
Then Loki saw in what a dangerous situation he was. He must risk his life if he swam out to sea. The only other alternative was to leap over the net. That he did, jumping as quickly as he could over the top cord.
Thor snatched at him, and tried to hold him, but he slipped through his hand, and would have escaped, but for his tail, and this is the reason why salmon have their tails so thin.
Loki being captured, they took him to a certain cavern, and they took three rocks, through each of which they bored a hole. Then they took Loki's sons Vali and Nari, and having changed Vali into a wolf, he tore his brother Nari into pieces. Then the gods took his intestines and bound Loki with them to the three stones, and they changed the cord into bands of iron. Skadi then took a serpent and suspended it over Loki's head so that the venom drops from it on to his face. Siguna, Loki's wife, stands near him, and holds a dish receiving the venom as it falls, and when the dish is full she goes out and pours its contents away. While she is doing this, however, the venom falls on Loki, and causes him such intense pain that he writhes so that the earth is shaken as if by an earthquake.
There he lies till Ragnarök (the twilight of the gods).
From the Prose Edda.