The International Cricket Council says in a statement that Shakib pleaded guilty and accepted the sanction on Monday offered to him by match referee Chris Broad.
Shakib nearly hit Zimbabwe wicketkeeper Brendan Taylor when he smashed his bat onto his pads after being given out lbw off the bowling of Prosper Utseya.
Broad says such a reaction from the former Bangladesh captain was unacceptable and "when the umpire's finger goes up the batsman must leave the crease without showing his emotions".
Zimbabwe won the match by six wickets to level the series 1-1.