The Bodhisatta was once a king’s chaplain. One day a large fish was being affectionately playful with his wife as the pair swam in a river. She noticed that a fisherman had just tossed his net and she quickly swam around it. But she did not warn her amorous husband, who was snared. The fisherman tossed him on the sand and went to go light a fire for cooking.
The Bodhisatta went down to the river to bathe and heard this fish lamenting his fate. The fish was not upset over his impending death; rather that his wife might think he’d run off with another fish. The Bodhisatta pitied this fish because he knew if he died in this state of passion he would be reborn in hell.
The fishermen of this area provided the palace with one fish a day, so the Bodhisatta asked to take the large fish that had just been caught as the daily contribution. The Bodhisatta took the fish he had saved and sat on the riverbank, preaching to him to stop being a slave to passion and then threw him back into the river.
In the Lifetime of the Buddha
The two fish were earlier births of one of the Buddha’s disciples and his former wife. When the disciple began to long for her, the Buddha told him this story to let him know she was ultimately harmful to him and that he had saved him from her in a previous life.