Gorki Aguila, 39, was ordered to pay 600 Cuban pesos, or about $30, for playing his music too loud during rehearsal, his father Luis Aguila said.
The bushy-haired rocker was arrested on Monday as his band, Porno para (for) Ricardo, was recording its latest album.
News of the arrest quickly spread through the blogosphere and on Friday a crowd of foreign diplomats, foreign correspondents, government press officials and Aquila supporters waited in the street outside the court.
His songs have fiercely criticized Cuba's communist government and its leaders Fidel and Raul Castro, which band members blamed for his arrest.
The Cuban government has said nothing about the case.
The group's CDs are banned in Cuba but copies are circulated underground.
Aquila, who was led into court in handcuffs, was freed after the hearing, which was closed to the press.
The original charge of social dangerousness pertains to people who authorities believe are likely to commit crimes, and can include such things as habitual drunkenness, drug addiction and anti-social behavior.
Aguila went to prison previously on drug charges he said were the result of entrapment by the Cuban government.
The illegal but tolerated Cuban Human Rights Commission said its preliminary investigation of the latest charge found Aguila committed no crime and called for the case to be dismissed.
The human rights commission recently issued a report saying the Cuban government had 219 political prisoners behind bars and that short-term detentions of government opponents had increased dramatically in the first half of 2008.
Cuban officials view dissidents as mercenaries working with the United States to subvert its government. The United States has had a trade embargo against Cuba for 46 years and its diplomats in Havana openly work with the opposition.
(Reporting by Jeff Franks and Esteban Israel; editing by Michael Christie and Eric Beech)
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