Brahatsen was a powerful and Dharmik ( truthful )King of Midra desh. He had a very beautiful daughter named Laxmana ( 2nd Laxmana, the other was Duryodone's daughter ) . Brahatsen consulted with Naradji and created a Matsyavedhan Swayamver for his daughter. Brahatsen invited thousands of Kings, Princes and great warriors from all over Bharat.
The target was to shoot the fish in the Swayamver but it was higher and smaller than Draupadi's Swayamver. There was also a great divya bow that was supposed to be bent and strung before shooting the fish. Many kings and great warriors with knowledge of great weapons tried to perform this task. Some of them could not even lift the bow, while others did manage to lift the bow but could not bend it to string it.
There were great and mighty warriors such as Jarasandth, Shisupal, Rukmi, Ambast, Kalingraja, Vidurath, Dhantvark, Paudyak, Duryodone and Shaalv ( not Pandavs mama but a different king ). All these warriors were able to lift and string the bow but when they shot the arrow they could not hit the target. Finally, there were two great warriors that tried to perform the task. They were Arjun and Karna, both of them were more successful than others because they were able to hit the fish ( both of them were able to hit the fish, but the real target was the eye of the fish ) but still they failed.
When everyone failed, Krishna got up from his throne. Lord Krishna lifted the great bow and strung it like handling a toy. Krishna looked down at the water pool at the reflection of the fish and shot the arrow up, hitting the fish in the eye and throwing it in the water pool. At that moment, on earth and heaven there were great cheers. The Devas rained flowers on Krishna congratulating him. Laxmana, dressed in great clothes and jewelry came forward in a palquin and placed a garland around Krishna's neck.
Other Kings, Princes and warriors that were against Krishna came forward and challenged him for a battle. Krishna took his Sarang bow and snapped the string to make a great noise. Krishna shot many arrows and countered each and every weapon shot by his enemies. Krisha also shot arrows and broke their bows and took their crowns off their heads. Many of those Kings ran away when they could not defeat Krishna in the battle. Others that kept on fighting were tied up by Krishna shooting Nagpash arrows at them. Krishna alone defeated all the greatest warriors assembled there.
After the battle, Brahatsen decorated the hall, got his friends and relatives together and married Laxmana with Krishna according to traditions. Brahatsen gave many expensive clothes and jewelry, servants ( men and women ) elephants, horses, chariots and warriors to Krishna as a gift. With Laxmana as his 6th wife, Krishna entered Dwarka.
( The kings that fought Krishna were Jarasandth, Paudyak, Shaalv, Ambast, Kalingraja, Dhantvark, Vidurath and Duryodone. Karna watched the battle but did not participate. Arjun almost went in the battle but saw that Krishna alone was able to defeat all the warriors. )