Restoring Vision to
Richard Borowsky,PhD photographs by the author except as noted
Blind Cave Fish
Lacking eyes and pigmentation, cave-inhabiting fish (front) are remarkably different from surface individuals (back).
The blind Mexican cave tetra Astyanax mexicanus is a perennial favorite among fishkeepers for its odd looks and easy maintenance in aquariums. Just about every other fish species we know of has
eyes and well-pigmented scales or skin, but
not this fish. However, we have discovered
that it is possible to reverse the course of
tens of thousands of years of evolution
and breed two completely blind cave tetras
together and get offspring that can see!
The First Specimens
The blind cave tetra was brought to the
attention of aquarists and scientists 75 years
ago by the Mexican biologist and collector
Salvador Coronado, who discovered the fish
in Cueva Chica, in northeastern Mexico.
He collected and shipped 75 specimens to
a dealer in the United States, and they all
arrived alive and healthy.
A Wide Range
Since their initial discovery, these fish
have been found in 28 other caves, which
are scattered over a broad area in northeast
Mexico. Each cave has its own special
dangers. For example, a mask is required in
Cueva Chica to avoid getting a fungal lung
infection called histoplasmosis. Several
members of Breder’s first expedition nearly
lost their lives from this disease.
Molino Cave is a pit cave with a 220-foot
drop from its lip to the bottom where the
fish are. It is reachable only by rope and