Tropical fish were not as yet popular in Southern California, but they were called for in the script as one of the film's most important sets was a solarium filled with fish tanks, most remarkably, Siamese fighting fish. Pet stores did not stock them as there was no demand. Then an advanced collector located in the San Fernando Valley agreed to have his collection rented. The appearance of tropical fish in "The Dragon Murder Case" was the spark that boosted tropical fish sales nationwide.

According to a contemporary article in the Motion Picture Hearald, this is the first "Philo Vance" film to star Warren William instead of William Powell.