On Fri, 6 Sep 1996, John Kalish wrote:
> A colleague would like to know if there are any thermophilic fish that
> inhabit waters of 45 to 50 degrees C or warmer. Hydrothermal vent fish may
> encounter water in this range, but don't appear to spend much, if any, time
> at these temperatures. This seems to limit the possible habitats to
> artesian systems. Any clues would be appreciated.
The highest temperatures naturally inhabited by fish are usually
associated with the pupfishes (Cyprinodon). C. atrorus was recored in
the wild at 47.2oC by Minckley (Minckley & Deacon 1969), Gambusia marshi
has also been caught at 44oC. There are two pupfish in northern Mexico
which apparently live and BREED at around 44oC, one is C. pachycephulus,
the other is undescribed (Minckley & Minckley 1986; Smith and Chernoff
1981). There are a number of records of fish occuring naturally in water
between 40 and almost 44oC. I would be most interested in anyone knows
of any data on fish other than pupfish/gambusia that have been found in the
wild at temperatures over ~42oC beit freshwater or marine. I'm sure some
of the Aphanius will probably do it. Oreochromis alcalicus grahami has
been caught at 42.8oC. One also needs a degree of caution in how the
temperature was measured as one usually finds distinct temperature layers
which can be very narrow. Obviously, unless the one the fish are living
in is measured the data will not be correct as had occured several times
in the past.
Minckley & Deacon. 1974. Desert fishes. In (Ed.) Brown. Desert Biology.
Minckley & Minckley. 1986. Cyprinodon pachycephalus, a new species of
pupfish from the Chihuauhan desert of northern Mexico. Copeia. 1986(1):
Smith & Chernoff. Breeding populations of cyprinodontoid fishes in a
thermal stream. Copeia. 1981(3): 701-702.
Peter J Unmack [log in to unmask]
PO Box 1454
Tempe AZ 85280-1454, USA
DESERT FISHES RULE: To boldly thrive where no other fish can make it!
Check out the Australian desert fishes pages at
just click on the Australian portion of the map