The hosts won the first Test of the three-match series by 27 runs but Fleming was not satisfied with the performance.
''Every area needs improving and that's more about attitude than skill,'' he told New Zealand Press Association.
''It's a lot easier when you're 1-0 up with a Test win. You can dissect areas that weren't special and move forward in a positive vein instead of trying to worry about the fallout of a Test loss.'' New Zealand have called up Kyle Mills as cover for seamers Shane Bond, Chris Martin and James Franklin, who are all carrying minor injuries.
''You don't really want to discard anyone,'' Fleming said. ''The characteristics of the pitch can change so quickly everyone's still in the mix.
''Even though some guys may not have picked up wickets and been below par, they should improve as the Test series goes on and too often we've probably chopped and changed and brought new players in.'' West Indies will name in-form batsman Runako Morton in their side as a replacement for the injured Ramnaresh Sarwan, and fast bowler Daren Powell looks likely to replace Jerome Taylor who has a hamstring injury.