Bobby Shmurda -- Knuckles Up for Crips vs. Bloods ... Jailhouse Edition

Bobby Shmurda had to bust out his quick hands when a gang war erupted in his NYC jailhouse.

Shmurda and 5 other inmates were cleaning house during the brawl last month in Otis Bantum Correctional Center ... according to law enforcement sources.

We're told the brawl was in full swing when guards came upon the inmates punching the crap out of each other. A little color commentary -- the combatants included an accused burglar, shmurderer, sodomist, and kidnapper.

Jail officials believe it was a Bloods and Crips thing -- we're told 4 of the inmates, including Bobby, are Crips ... while the other 2 are Bloods. Guards broke up the melee with 3 blasts of a pepper spray like "chemical agent."

Shmurda's locked up awaiting trial on conspiracy charges. His attorney had no comment on the jail brawl ... which, by the way, went down on April 15.

Even inmates hate taxes.