Tyga's Crew Brawls with EDM DJs in Stage Pissing Match

Tyga's cruise ship performance ended with a bang, a full-on fight between his hype man, DJ S.B. and one of the guys from EDM trio Cash Cash -- what's up for debate is ... who started it.

Things went south early Saturday morning aboard the Inception at Sea cruise festival. Tyga started his set more than an hour late ... which eventually postponed Cash Cash, which was going on after him.

Sources close to Tyga tell TMZ ... when he wrapped up, the Cash Cash guys began unplugging S.B.'s gear. That sparked a verbal dispute, and then Jean Paul Makhlouf allegedly threw the first punch.

Now, the Cash Cash guys admit there was a verbal altercation, but claim Tyga's crew struck first. Makhlouf suffered a concussion, injured kidney and several bruises, according to his rep. Cash Cash was unable to perform.

No one's talking lawsuit ... yet, anyway.

We're told Tyga had nothing to do with the fight, he was already offstage.