he was just swimming around trying to catch some food when he swam into a net, while trying to escape he hit the side of the boat and fall unconscious.

when he woke up he found himself in a massive tank filled with large rocks, coral, seaweed and some fish. At the front was a large glass wall, which looked into a large room. Swimming around he come to the surface which looked into a room which had large pumps and cleaning supplies.

it turns out he was bought by some rich guy and was now in his house. The rich guy threw a party and the room was filled with people, all looking at him. To escape the stares he swam into the room above and lay out of the water, appreciating the warmth from heating lights above.