FCZ are 10th of 12 teams in the Swiss Super League, with their latest result a 2-1 home defeat to Young Boys at the weekend where they finished with nine men after Alexandre Alphonse and Xavier Margairaz were sent off within a minute of each other early in the second half.
The Swiss side began their group campaign with a 2-0 defeat at home to Sporting Lisbon, and now face a tough test against a Vaslui side who drew their opening match away to Lazio in Rome.
Fischer knows his team must work on their temperament if they are to improve both domestically and in Europe.
He was quoted as saying in tagesanzeiger.ch at the weekend: "I've never experienced this before but I sensed that our emotions were at the limit. During half-time I had to warn my players to watch out because (Silvan) Aegerter and (Yacine) Chikhaoui stood close to red cards in the first half.
"This should not happen, such lack of self-control harms us tremendously. In particular, Margairaz is vice-captain so it is not easy to let that go. But it fits our situation. I want to look at the video again and then I will discuss it with my players."
Asked why his team rallied after the double dismissals, Fischer said: "That will always be the way. After the two dismissals my team came together because they felt aggrieved. But we should have shown this passion from the first minute."
Zurich have won only one of their last five games in all competitions, thrashing Grenchen 5-0 in the Schweizer Pokal.
Vaslui are seventh in the Romanian top flight, with four wins, one draw and three defeats from their eight games so far. They have won three of their last four league matches, including a 2-0 home victory over Vointa Sibiu last time out.
Their Brazilian forward Wesley has scored seven goals in his last five matches, including both in the win over Sibiu.