The money-spinning doctor who swapped medicine to breed black soldier flies

Independent

15-07-2025

A former doctor in Cuba, Yodermis Diaz Hernandez, now earns more cultivating black soldier flies for fish feed than he ever did practising medicine.
From a rudimentary workshop on Havana 's outskirts, Diaz incubates the insects, utilising equipment crafted from scavenged materials – a common necessity across Cuba.
These flies are gaining global attention, with initiatives in France, the Netherlands, and the UK investing in their farming over the past decade.
Their larvae are voracious waste consumers, devouring urban and agricultural biological refuse to produce protein-rich maggots.
These can then be processed into animal and pet food, a process Diaz notes comes at a remarkably low cost.
"A friend gave me the idea in 2019 after I had practiced internal medicine for over 20 years, and that broadened my horizons," he said.
That year, new US sanctions hit the Communist-run country, on top of a decades-old trade embargo.
The pandemic then crippled tourism and domestic industry, and inefficiencies in the state-run model slowed the recovery, leaving the Caribbean island nation short of cash to import just about everything. A long economic downturn followed.
The government last year began looking into the benefits of raising flies to make up for a dramatic drop in imported feed for livestock. Diaz said a handful of people in Cuba have begun their own small enterprises.
Last year, Diaz sold 300 kilograms of larvae to freshwater fish farms in Cuba, with each kilogram selling for 450 pesos (around $3.75, at the official exchange rate when dollars are available).
He hopes to sell 1,000 kg this year. That is many times what he could have earned as a doctor, though he says his main interest is sustainability for Cuba.
"We convert that garbage into protein, into gold for the animals, and the waste into fertiliser. We also help the environment," Diaz said.