I am attempting to document the fact that during the construction of
the Panama Canal, millions of guppies were imported from Trinidad to
reduce the mosquito population, thereby allowing successful completion
of the project while reducing illness and death of construction
workers.

"Gorgas used the military authority to his advantage while trying to
clean up Havana.... Larger bodies of water, such as ponds, were oiled
or filled with mosquito-eating fish..."

"After Havana became malaria-free, the government decided to begin
building the Panama Canal again. They hired Gorgas to get rid of the
mosquitoes. He used the same kind of rules in Panama as he did in
Havana."
http://www.pinoak.us/projects/buzzoff/research.html

This gets me close, but there is actually a fish called the mosquito
fish (gambusia affinis), which, although closely related, is not
Poecilia (Libestes) Reticulata - Peters 1859. Would really like to fnd
the word "guppy" in the source material. Thanks.