What was found
ODOR IN CABIN REPORTED BY FA/PASSENGERS. NOT SMOKE OR ELECTRICAL ODOR. REMOVED FROM SERVICE. ODOR DESCRIBED AS A OLD DIRTY / STALE FISH SMELL. MOST NOTED IN THE FIRST CLASS SECTION. C/W AIR CONTAMINATION CHECK LIST, FORM M-744. INSPECTED CARGO COMPARTMENTS, NO SMELLS NOTED. CLEANING CREW CLEANED CABIN, HOOKED UP PCA, SMELL HARDLY NOTED NOW. A/C OK FOR SERVICE. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.