It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) that he said: "We stopped at a place and the fleas troubled us, so we cursed them. The Messenger of Allah (peace and blessings be upon him) said: 'Do not curse them; what an excellent creature it is, for it woke you up for the remembrance of Allah.'"
Imam al-Tabarani (may Allah have mercy on him) said: "This hadith is narrated from Sayyiduna Ali (may Allah be pleased with him) only with this chain; Adam is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الهاء / 9318
Hadith Gradingمحدثین:إسناده ضعيف جدًّا، فيه سعد بن طريف متروك
Hadith Takhrij«قال الهيثمي: فيه سعد بن طريق وهو متروك «مجمع الزوائد ومنبع الفوائد، ج 8، ص 78»» «أخرجه ابن حجر فى «المطالب العالية» برقم: 2719»