[RML] Archerfish

Bruce Hansen (bruceh at powerup.com.au)
Thu, 26 Jul 2001 08:07:45 +1000

G'day All

For those of you that find "other than Rainbow"fish interesting - most
fishkeepers know all about those amazing members of the genus Toxotes and
how they have the unique
ability to "shoot" down insects from overhanging branches with a jet of
water. How have they developed this accuracy considering the optical
challenges associated with parallax effects at the air-water interface - the
insect is in the air and the eye of the fish is underwater? This has
intrigued scientists ever since these sharpshooters were discovered.

One of my friends has a very nice Archer in a 3 foot tank who regularly
shoots his crickets and moths on request. Carl also regularly supplies small
fish and shrimp from the local creek and this particular Archer is
much-loved and much observed. However much one reads on fish behaviour, it
is always a joy to hear something new and especially when it has been
observed by an enthusiastic amateur. Carl observed that his Archer would
hunt and devour as many small fish and shrimp as he could by chasing them
around the tank. Eventually only a few would be left hiding in the "safe "
places in the corners between the driftwood and the backdrop where the
Archer could not enter. Our intrepid Archer then simply squirted a powerful
jet of water into the corner to dislodge the unwary prey out of the safety
and into the open to become lunch. I would be interested to hear if anyone
else has seen this happen. Obviously the "calculation" required to be on
target underwater is entirely different to above-water targets.

Regards,
Bruce ( Hansen )
vicepresident - ANGFA Inc (www.angfa.org.au)
- ANGFA (Qld) Inc (www.angfaqld.org.au)