The brother of NBA star DeMarcus Cousins was tased and arrested for fighting in a Tampa nightclub early this morning ... but we're told DeMarcus was pulled away from the fracas before cops got involved.
Both DeMarcus and Jaleel Cousins had been partying at The Drynk SoHo (see pic of the two below) when things got heated with club security.
Sources inside the club tell us the brothers tried to get in to the DJ area but security was shutting them down -- and that's when the chest-puffing began.
In footage obtained by TMZ Sports, you can see Jaleel throwing a haymaker punch -- while chaos ensues around him.