Two men were reportedly arrested inside the apartment, where officers found 37 cannabis plants, as well as the insects.
The suspects are being investigated for animal welfare violations, as well as drug-related charges in connection to their arrests.
The drug raid took place on Wednesday (February 2) after officers were told a strong cannabis odor was coming from a building in a northeast Brussels neighborhood.
Police searched the apartment, which led to the arrest of a man and his adult son.
In total, officers seized the 37 cannabis plants, as well as 52 tarantulas, a python, three scorpions, four turtles, two lizards in the Pogona family (bearded dragons) and 16 beetles, the AP reports.
No additional details have been released in connection to the incident.
Cannabis is one of the most popular controlled substances in Belgium despite technically being illegal in the European country, though personal possession was decriminalized in 2003.
Adults over the age of 18 are allowed to possess up to three grams.
In 2015, Maggie De Block signed a royal decree to legalize medicinal cannabis, though the order only included Sativex oral spray for multiple sclerosis treatment.